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1.
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
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
2.
Yeon-Soo Jang 《Environmental Earth Sciences》2013,69(3):987-997
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
3.
The leachate levels in the landfills in southern China are generally high. Field monitoring was carried out in the Suzhou landfill to investigate the leachate mound. The saturated hydraulic conductivity and soil–water characteristic curve (SWCC) of municipal solid waste were measured using samples taken from different depths of the landfill. Field monitoring reveals that a perched leachate mound and a substantial main leachate mound existed in the landfill. The saturated hydraulic conductivities of wastes in shallow, middle and deep depth were measured to be 4.81 × 10?2, 3.50 × 10?3 and 3.56 × 10?4 cm/s, respectively. The results of SWCC tests show that the SWCC curve was steep when matric suction was low, and the shallower the waste the steeper would be the curve. In addition to the field and laboratory tests, an unsaturated–saturated seepage analysis was conducted to simulate the development of the high leachate mound and to calculate the annual leachate production. The simulated volumetric water content in the unsaturated zone was about 40 %, which agreed well with the test result. The calculated leachate mound was consistent with the field measurement. The calculated annual and daily leachate productions were all more reasonable than the results of the HELP model. 相似文献
4.
5.
Aquifer vulnerability assessment using the DRASTIC model at Russeifa landfill,northeast Jordan 总被引：1，自引：0，他引：1
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
6.
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
7.
Testing the ability of bentonite-amended natural zeolite (clinoptinolite) to remove heavy metals from liquid waste 总被引：2，自引：0，他引：2
The design of environmentally sound liquid waste containment structures has become a crucial task in engineering applications
due to ever increasing groundwater contamination from such sites. Construction of such structures usually requires a bottom
liner of low hydraulic conductivity as part of the design. In order to reduce the hazards associated with liquid wastes including
landfill leachate, bentonite-amended natural zeolite is proposed as an alternative to conventional earthen liners. Among many
contaminants associated with liquid wastes, heavy metals are the most dangerous ones. This paper deals with determining the
ability of natural zeolite to remove heavy metals from aqueous waste. For this purpose, crushed natural zeolite (clinoptinolite)
is amended with commercial powdered bentonite to yield a soil mixture low in permeability and high in ion-exchange capacity.
Leachate from a conventional landfill is used as the percolation fluid. Concentrations of certain heavy metals in the effluent
fluid percolated through the bentonite-zeolite mixture are compared with that of initial leachate. The conclusion is reached
that certain metals are efficiently removed from the influent solution by the soil matrix whereas some ions do not show significant
reduction in concentration. This is attributed to high hydraulic conductivity of the bentonite-zeolite mixture. 相似文献
8.
The Nanjido Landfill is the largest uncontrolled landfill in Korea and it causes various kinds of environmental problems.
Landfill gases and leachate are recognized as the most serious environmental problems associated with the landfill. This study
employs a series of numerical models and uses test data to interpret the distribution and flow of landfill gases and leachate.
Leachate seepage appears about 40–60 m higher than the estimated basal groundwater table. Thus, seepage data indicate that
perched or floating leachate layers are formed in the unsaturated zone of the landfill. The leachate production rate is estimated
using infiltration test data and a model for unsaturated groundwater flow. Geochemical data indicate that the landfill leachate
degrades the basal groundwater quality along the downgradient zone. The environmental impact of the leachate on river water
is estimated.
Received: 17 June 1996 · Accepted: 2 October 1996 相似文献
9.
Yucca Mountain, the proposed site for the high-level nuclear waste repository, is located just south of where the present
water table begins a sharp rise in elevation. This large hydraulic gradient is a regional feature that extends for over 100 km.
Yucca Mountain and its vicinity are underlain by faulted and fractured tuffs with hydraulic conductivities controlled by flow
through the fractures. Close to and parallel with the region of large hydraulic gradient, and surrounding the core of the
Timber Mountain Caldera, there is a 10- to 20-km-wide zone containing few faults and thus, most likely, few open fractures.
Consequently, this zone should have a relatively low hydraulic conductivity, and this inference is supported by the available
conductivity measurements in wells near the large hydraulic gradient. Also, slug injection tests indicate significantly higher
pressures for fracture opening in wells located near the large hydraulic gradient compared to the opening pressures in wells
further to the south, hence implying that lower extensional stresses prevail to the north with consequently fewer open fractures
there. Analytical and numerical modeling shows that such a boundary between media of high and low conductivity can produce
the observed, large hydraulic gradient, with the high conductivity medium having a lower elevation than the water table. Further,
as fractures can close due to tectonic activity, the conductivity of the Yucca Mountain tuffs can be reduced to a value near
that for the hydraulic barrier due to strain release by a moderate earthquake. Under these conditions, simulations show that
the elevation of the steady-state water table could rise between 150 and 250 m at the repository site. This elevation rise
is due to the projected shift in the location of the large hydraulic gradient to the south in response to a moderate earthquake,
near magnitude 6, along one of the major normal faults adjacent to Yucca Mountain. As the proposed repository would only be
200–400 m above the present water table, this predicted rise in the water table indicates a potential hazard involving water
intrusion.
Received: 7 June 1996 / Accepted: 19 November 1996 相似文献
10.
A multi-layered aquifer, typical of riverbank alluvial deposits in Korea, was studied to determine the hydrologic properties.
The geologic logging showed that the subsurface of the study site was comprised of four distinctive hydrogeologic units: silt,
sand, highly weathered and fresh bedrock layers. The electrical resistivity survey supplied information on lateral extension
of hydrogeologic strata only partially identified by a limited number of the geologic loggings. The laboratory column tracer
test for the recovered core of the sand layer resulted in a hydraulic conductivity of 5.00×10−2 cm/s. The slug tests performed in the weathered rock layer yielded hydraulic conductivities of 4.32–7.72×10−4 cm/s. Hydraulic conductivities for the sand layer calculated from the breakthrough curves of bromide ranged between 2.08×10−3 and 2.44×10−2 cm/s with a geometric mean of 6.89×10−3 cm/s, which is 7 times smaller than that from the laboratory column experiment. The trend of increasing hydraulic conductivity
with an increase in tracer travel length is likely a result of the increased likelihood of encountering a high conductivity
zone as more of the aquifer is tested. The combined hydrogeologic site characterization using hydraulic tests, tracer tests,
and column test with geologic loggings and geophysical survey greatly enhanced the understanding of the hydrologic properties
of the multi-layered alluvial aquifer. 相似文献
11.
Preventing the penetration of rainwater into a landfill site is the main purpose of the final cover in landfill sites. Conventional designs of landfill covers use geotextiles, such as geomembrane and geosynthetic clay liners, and clay liners to lower the permeability of the final cover of landfill sites. However, differential settlement and climatic effects in landfill sites instigate crack development or structural damage inside the final cover. This study therefore investigates the field applicability of a self-recovering sustainable liner (SRSL) as an alternative to the landfill final cover. The SRSL utilizes the precipitation reaction of two chemical materials to form precipitates that fill the pores and thereby lower the overall permeability of the liner. To examine the field applicability of the SRSL system, uniaxial compression tests and laboratory hydraulic conductivity tests were performed under various climatic effects such as wet/dry and freeze/thaw processes. Furthermore, field-scale hydraulic conductivity tests were performed with intentionally induced cracks to demonstrate the self-recovery performance for practical applications. Extensive laboratory and field test results confirmed the capability of the SRSL final cover system to fulfill the strength and hydraulic conductivity requirements, even in harsh field conditions. 相似文献
12.
Shear strength characterization of municipal solid waste at the Suzhou landfill, China 总被引：5，自引：0，他引：5
The current practice of slope stability analysis for a municipal solid waste (MSW) landfill usually overlooks the dependence of waste properties on the fill age or embedment depth. Changes in shear strength of MSW as a function of fill age were investigated by performing field and laboratory studies on the Suzhou landfill in China. The field study included sampling from five boreholes advanced to the bottom of the landfill, cone penetration tests and monitoring of pore fluid pressures. Twenty-six borehole samples representative of different fill ages (0 to 13 years) were used to perform drained triaxial compression tests. The field and laboratory study showed that the waste body in the landfill can be sub-divided into several strata corresponding to different ranges of fill age. Each of the waste strata has individual composition and shear strength characteristics. The triaxial test results showed that the MSW samples exhibited a strain-hardening and contractive behavior. As the fill age of the waste increased from 1.7 years to 11 years, the cohesion mobilized at a strain level of 10% was found to decrease from 23.3 kPa to 0 kPa, and the mobilized friction angle at the same strain level increasing from 9.9° to 26°. For a confinement stress level greater than 50 kPa, the shear strength of the recently-placed MSW seemed to be lower than that of the older MSW. This behavior was consistent with the cone penetration test results. The field measurement of pore pressures revealed a perched leachate mound above an intermediate cover of soils and a substantial leachate mound near the bottom of the landfill. The measurements of shear strength properties and pore pressures were utilized to assess the slope stability of the Suzhou landfill. 相似文献
13.
首先对斑脱土衬里(粘土-斑脱土、砂-斑脱土) 进行变水头实验, 得粘土-斑脱土的渗透系数为6.0×10-9~3.0×10-8cm/s, 砂-斑脱土的渗透系数为1.0×10-9~3.0×10-9cm/s.从防渗角度分析, 2种斑脱土混合物均适合作垃圾填埋场的底层衬里.然后对斑脱土衬里进行持水与水迁移实验, 评价斑脱土衬里水的迁移特性.以水迁移实验为基础, 模拟斑脱土衬里与地基5种不同含水量的条件, 对斑脱土衬里进行直接剪切实验, 测定斑脱土衬里的剪切强度及斑脱土衬里与地基接触面的剪切强度.再对斑脱土衬里进行三轴固结不排水实验, 测定其总剪切强度与有效剪切强度.实验结果表明: 地下水具有很大的潜力从地基流向斑脱土衬里, 从而大大提高斑脱土衬里的含水量; 随着含水量的增加, 粘土-斑脱土、砂-斑脱土衬里的抗剪强度逐渐减小.根据实验所获得的抗剪强度参数, 选择日本山谷型垃圾填埋场典型剖面, 对山谷型垃圾填埋场进行稳定性评价.结果表明: 对于角度小于20°的缓倾角山谷型垃圾填埋场, 使用粘土-斑脱土、砂-斑脱土作为底层衬里是稳定的.因此, 2种斑脱土混合物适合作山谷型垃圾填埋场的底层衬里. 相似文献
14.
针对非卫生垃圾填埋场环境污染问题,以某垃圾填埋场为例,通过 WHI UnSat Suite软件 HELP模块计算不同填埋条件下渗滤液渗漏量。利用GMS模拟了该垃圾场中心抽水条件下污染物迁移变化规律。结果表明,简单地表防渗条件下,渗滤液渗漏量为现状条件下的50%,增铺 HDPE土工膜后,渗漏量可减少99%。卫生填埋渗滤液仅为现状条件下的3.6＆#215;10-3倍。当抽水量为2000 m3/d时,Cl-浓度呈明显下降趋势,由84 mg/L降至80.1 mg/L。 相似文献
15.
垃圾土渗透性和持水性的试验研究 总被引：5，自引：2，他引：3
通过室内常水头试验测定了垃圾土的饱和渗透系数,通过室内压力板仪试验测得垃圾土的土-水特征曲线。基于土-水特征曲线预测了垃圾土的非饱和渗透系数,并通过室内入渗试验进行了初步验证。常水头试验得到深层、中层和浅层垃圾土的饱和渗透系数分别为3.56×10-4、3.50×10-3、4.81×10-2 cm/s。土-水特征曲线试验表明,垃圾土饱和含水率和残余含水率较高,进气值很小,土-水特征曲线在低基质吸力时存在陡降段,其中浅层垃圾土的陡于深层垃圾。验证试验表明,预测得到的非饱和渗透系数与实测结果接近,基于土-水特征曲线预测垃圾土非饱和渗透系数的方法基本可行。 相似文献
16.
Generalized equations using fractional-flow dimensions were derived to estimate the Darcy and seepage velocities obtained
from the point-dilution and the single-well injection-withdrawal field tests conducted in fractured-rock aquifers. Seepage
velocities can only be estimated from single-well tests if the hydraulic conductivity and the hydraulic gradient are known
a priori. However, if a radial-convergent test is also performed between two boreholes, the kinematic porosity can be estimated
and be used to estimate the seepage velocity from the single-well test results.
To apply the generalized equations, the flow dimension and the extent of the flow region must be known. Therefore, the generalized
radial flow (GRF) model of Barker (1988; a generalized radial flow model for hydraulic tests in fractured rock. Water Resour
Res 24(10):1796–1804) is used to estimate the flow dimension because of its wide range of applications. A pumping test performed
on the boreholes will yield an estimate of the fractional-flow dimension by applying the GRF model.
Electronic Publication 相似文献
17.
The Burwood landfill, which serves the city of Christchurch, New Zealand, is situated on coastal sands underlain by a sequence
of aquifers and aquitards. Groundwater flow is toward the coast, located approximately 700 m from the landfill boundary. Shortly
after completion of the first phase of the landfill, an array of wells was installed to detect any contaminant from the landfill.
Leachate was detected in the wells closest to the landfill. A shallow electromagnetic (EM31) survey was carried out between
the landfill and the coast, in order to delineate any leachate plume that may be present. On the basis of the geophysical
results, a contaminant plume and buried channels connected to the coast were identified. Leachate flow initially occurs in
what is probably a channel or pair of channels. Downgradient, the plume spreads out to the north and south as it moves eastward
toward the coast. Using the geophysical results as a guide, a new set of wells was installed to confirm the presence of high
leachate concentrations. Pore-water sampling confirms the presence of a leachate plume.
Received, June 1998 /Revised, March 1999, January 2000/Accepted, January 2000 相似文献
18.
Large quantities of leachate-contaminated lateritic soil results from dump yards in the southwest coast of India. These dump yards receive large quantities of municipal solid waste which includes chemical, industrial and biomedical wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the compaction characteristics and hydraulic conductivity of clean and contaminated lateritic soil. Batch tests were used to study the immediate effect of leachate contamination on the properties of lateritic soil. Contaminated specimens were prepared by mixing the lateritic soil with leachate in the amount of 5%, 10% and 20% by weight to vary the degree of contamination. The results indicated a small reduction in maximum dry density and an increase in hydraulic conductivity due to leachate-contamination. The change induced by chemical reaction in the microstructure of the soil was studied by scanning electron microscope before and after contamination of soil with leachate. The structure of the leachate contaminated soil sample appeared to be aggregated in scanning electron microscope analysis. The aggregated structure increases the effective pore space and thus increases the hydraulic conductivity. Fifty percent increase in hydraulic conductivity was observed for specimens prepared at standard Proctor density and mixed with 20% leachate. Compaction characteristics did not change much with the presence of leachate up to 10%. With 20% leachate the maximum dry density decreased slightly indicating excess leachate in the soil. However the changes are not significant. 相似文献
19.
Rajiv K. Giri 《Geomechanics and Geoengineering》2015,10(2):126-138
In bioreactor landfills, different configurations of closely spaced horizontal trench (HT) systems are often considered as leachate recirculation systems to achieve uniform and rapid distribution of moisture in municipal solid waste (MSW). In this study, a numerical two-phase flow modelling was adopted to study the effects of geometric configuration of HT systems on the moisture distribution in MSW, and the stability of a simplified bioreactor landfill slope during continuous and intermittent leachate recirculation. Transient variations in pore water and capillary pressures in MSW were assessed, and slope stability analyses were performed using strength reduction technique. MSW was considered as heterogeneous and anisotropic with varied unit weight and saturated hydraulic conductivity. The results demonstrated that geometric configurations of HT systems significantly affected the moisture distribution, generation and distribution of pore water and capillary pressures in MSW, and considerably influenced the mechanical stability of bioreactor landfill slope. It was concluded that staggered configuration of closely spaced HT systems with intermittent sequences of leachate recirculation and subsequent gravity drainage in alternate shallow and deep HT layers should be adopted as they produce uniform moisture distribution and ensure the mechanical stability of landfill slope due to low induced pore pressures near side slope. Overall, this study presents a significant contribution to the understanding of the basic mechanisms controlling the geotechnical stability of bioreactor landfills during leachate operations. Furthermore, the capability of the adopted commercial code was verified with complexities related to bioreactors behaviour. However, further research is needed to validate the model based on field monitoring data at actual bioreactor landfills. 相似文献
20.
The soil around a drain well is traditionally divided into smeared zone and undisturbed zone with constant hydraulic conductivity. In reality, hydraulic conductivity of the soil changes continuously and it may not be always appropriate to approximate its distribution with two zones. In this study, the horizontal hydraulic conductivity of the soil is described by an arbitrary function of radial distance. The horizontal flow under equal strain condition is analysed for a soil–drain system with a circular or regular polygonal boundary. It is found that the horizontal flow can be generally characterized with a linear equation in which the flow rate of water through soil–drain interface is proportional to the difference between the average excess pore pressure in the soil and the excess pore pressure in the drain well. The water exchange between the drain and the soil is analogous to that between fractures and matrix in a double porosity system, a popular conceptual model of fracture rocks. On the basis of this characterization, a simplified approach to analyse soil–drain systems is developed with one‐dimensional double porosity model (DPM). Analytical solutions for both fully and partially penetrating drains are derived. The solution for partially penetrating drains is compared with both numerical and approximate analytical results in literature. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献