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1.
Analysis of flow behavior in a landfill with cover soil of low hydraulic conductivity 总被引：2，自引：1，他引：1
Y. -S Jang 《Environmental Geology》2000,39(3-4):292-298
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
2.
为了研究区域土壤氡填图的方法,利用RAD7电子测氡仪和RADON-JOK土壤气体渗透率仪在广东省中山市进行了面积为1 800 km2的测量工作,有效测点数为67个。中山市的平均土壤氡浓度为(100.41±154.64)kBq/m3;最大值和最小值分别为0.74 kBq/m3和1 199.24 kBq/m3。土壤气体渗透率测量结果表明,在风化花岗岩地区,高渗透率和中渗透率占优势;而第四纪沉积物地区大部分土壤气体渗透率较低。基于此,结合研究区土壤氡浓度和土壤气体渗透率,对研究区土壤氡风险进行了分级评价。为土壤氡风险分级的方法研究提供了有参考价值的研究实例。 相似文献
3.
Variations in soil gas Hg, Rn and He concentrations and meteorological variables were monitored daily at one site over a period of 22 months. Air and soil temperature, humidity, barometric pressure, soil moisture, wind direction and velocity, soil freeze-thaw, water table elevation, crystal strain and gas emissions were determined simultaneously in order to assess the influence of the environmental variables on gas emission.Mercury concentrations were found to be higher in the summer while Rn and He concentrations were higher in the winter. It is hypothesized that adsorption-desorption controls the migration of Hg whereas Rn and He concentrations are controlled by diffusion and mass transport. Gas emissions respond to seasonal and shorter-term changes in environmental conditions. Stepwise multiple regression using gas emissions as the dependent variables suggests that environmental parameters account for 62% of the total Hg variance, 83% of the total Rn variance, and 33% of the total He variance. Temperature, barometric pressure and soil moisture exert the most influence on gas emissions with temperature effects dominating gas emissions throughout the year. Soil gas emissions display a predictable behavior during winter and summer when more stable meteorological conditions exist. During the transitional seasons of spring and fall, soil gas emissions become erratic and exhibit increased variability. Environmental variables are interrelated and appear to control the manner of gas migration.Increased adsorption by solids during the season of falling temperature decreases soil gas Hg<0.0001 ng L−1, which is desorbed as the soil warms in the spring. Transport of Rn and He is primarily by convection. During the winter months, air temperatures are less than soil temperatures promoting upward movement of Rn and He by convection. During the summer, soil temperatures are less than air temperatures and an inversion layer below the level of sampling reduces upward flux and observed concentration. 相似文献
4.
The Judith River Formation forms an important regional aquifer in southwestern Saskatchewan, Canada. This aquifer is used for domestic and agricultural purposes in some areas and supports oil and gas production in other areas. As a result, the available data come from a range of sources and integration is required to provide an overview of aquifer characteristics. Here, data from oil and gas databases are combined with data from groundwater resource assessments. Analysis of cores, drill-stem tests and pumping tests provide a good overview of the physical hydrogeology of the Judith River Aquifer. Water chemistry data from oil and gas databases were less helpful in understanding the chemical hydrogeology due contamination of samples and unreliable laboratory analyses. Analytical modeling of past pumping in the aquifer indicates that decreases in hydraulic head exceeding 2 m are possible over distances of 10s of kilometers. Similar decreases in head should be expected for additional large withdrawals of groundwater from the Judith River Aquifer. Long-term groundwater abstraction should be limited by low pumping rates. Higher pumping rates appear to be possible for short-term uses, such as those required by the oil and gas industry. 相似文献
5.
Celestina Adu-Wusu Ernest K. Yanful Lisa Lanteigne Mike O’Kane 《Geotechnical and Geological Engineering》2007,25(2):215-237
Soil cover systems are widely used for containment of municipal solid waste, hazardous and mine waste, with the objective
of limiting the ingress of precipitation and oxygen. The ability to predict their long-term performance is crucial, as their
failure would result in the release of contaminants to the environment. However, monitoring covers over the long term to derive
the information needed to aid in design is impractical and there are no large-scale covers that have been in use for a long
enough period to generate the data needed. Numerical models have been particularly useful as design tools. To improve their
reliability these models may be calibrated to field data and then used to make long-term predictions of cover performance.
The field performance of two resistive test soil covers on a 20% sloping waste rock platform is predicted using the two-dimensional
soil–atmosphere model Vadose/W. Input data for the model included soil, climate and vegetation data obtained either in the
field or laboratory. Model results were compared to field data to assess the validity of the program. The model reasonably
simulated field response patterns for soil water storage and suction. Divergence between field performance data and model
predictions were significantly influenced by snowmelt, interflow and flow through preferential pathways. 相似文献
6.
In this paper, marble waste is evaluated as a secondary material to be utilized as potential stabilizer to improve the volume change and strength characteristics of sand-amended expansive soil, proposed as a possible landfill, pavement or sub-base material in a semi-arid climate. An experimental program was conducted on sand-expansive soil enhanced with marble waste, abundantly found as a by-product of construction industry, obtained from two different sources with different gradations, denoted as marble powder (MP) and marble dust (MD). One-dimensional swell, volumetric shrinkage, consolidation, unconfined compressive and flexural strength tests were conducted on expansive soil–sand mixtures with 5, 10 and 20% waste marble inclusions over curing periods of 7, 28 and 90 days. Test results showed that 10% marble powder and 5% marble dust by dry mass were the optimum amounts for mitigating the swell–shrink potential and compression index as well as yielding the highest unconfined compressive and flexural strength values. Moreover, the rate of reduction in swell potential versus the flexural strength over the curing periods studied is highest in 10% MP- and 5% MD-included specimens, the latter being more insensitive to this change. The soil mixtures displayed brittle behavior after marble addition, hence its utilization as a secondary additive to sand-amended expansive soil is recommended for soils exposed to lower flexural loads such as light traffic. 相似文献
7.
The occurrence of land subsidence in the Kingdom Saudi Arabia is either natural or man-made. Natural land subsidence occurs due to the development of subterranean voids by a solution of host rocks in carbonate and evaporite terrains, over many areas of Saudi Arabia. Man-induced land subsidence is either due to the removal of groundwater in the agricultural areas or to wetting of unstable soils. Therefore, earth fissures and a lowering of the ground surface in unconsolidated sediments took place in alluvial plains and volcanic vent terrains. Unstable soils include Sabkha soils and loess sediments. These types of soils occur in coastal plains, desert areas and volcanic terrains. When this soil is wetted either during agricultural activities, waste disposal or even during a rain storm, subsidence takes place due to either the removal of salts from the Sabkha soil or the rearrangement of soil particles in loess sediments. 相似文献
8.
Waste dumps generated from mining that exposes sulfur-bearing overburden can be active sources of acid generation with the potential to severely contaminate soils, surface and groundwater, and endanger both local and downstream ecosystems. A waste rock management strategy ensure that disposal of such material is inert or at least stable and contained, and minimizes the surface footprint of the wastes, and explores options for alternate uses. Reclamation of waste dumps is another or parallel alternative to decrease the potential for adverse effects. At the coal mining area of Karmozd in Iran, large volumes of wastes have been produced and disposed of without any specific care for the environment. In this paper, the impacts of waste dumps on the environment were identified and this was followed by a research program to determine the characteristics of the wastes, their acid generation potential, the availability of hazardous contaminants, and a prediction of their environmental impacts on the site. Data was collected from the target site and by comparing several reclamation alternatives using a Multi-Attribute Decision-Making technique, forestry was selected as the post-mining land use for the waste dumps. Preliminary evaluations indicated that Zelkava could be a useful tree species for this region. 相似文献
9.
研究掺粉煤灰对合肥膨胀土的物理性质指标以及胀缩性指标等的影响,探讨利用粉煤灰改良膨胀土的措施与效果。试验研究结果表明,在膨胀土中掺入适量的粉煤灰可有效降低膨胀土的塑性指数、降低膨胀势、减小线缩率与降低活性。在膨胀土中掺入粉煤灰还可改变膨胀土的击实特性,一定击实功作用下,随着掺灰率的增加,土体的最优含水率与最大干密度均减小,膨胀土中掺入粉煤灰后,膨胀土可在较小的含水率下通过击实或压实达到稳定。掺灰膨胀土的膨胀量与膨胀力随养护龄期的增长而减小;没有经过养护的掺灰土,其无侧限抗压强度随掺灰率的变化几乎没有变化,经过7 d养护后,土的无侧限抗压强度有所增长,并且存在一个峰值点,合肥膨胀土的无侧限抗压强度所对应的最佳掺粉煤灰率约为15 %～20 %。 相似文献
10.
X-ray photography has been used to locate the position of a growing ice lens in soil under laboratory conditions in order to establish the temperature of the actively growing face by means of its position in the thermal gradient field. It can be shown that in a general way the phase change temperatures are predictable from the Clapeyron equation. The structure of the ice phase also appears to follow the predictions of the heave rate equation proposed by Penner and Ueda (1978). When heaving occurs at low overburden pressures, there is a tendency for the ice lens to be very discrete and essentially soil free; at higher pressures and under similar thermal gradients it tends to develop in a more diffuse band and over a much wider temperature range. 相似文献
11.
A careful selection of waste dumpsites, particularly hazardous ones, is very important for sustainable water resources management. Several laboratory experiments were carried out on the field samples to study adsorption capacity using p-dichlorobenzene (a solvent used in various industrial processes) as the test contaminant. The effect of parameters such as organic matter, clay, and iron and aluminium oxides, which are known to influence the soil adsorption capacity, are studied in the present work. Several soil samples from the Patancheru Industrial Area (Hyderabad, India) were collected and characterized. Only three soils, which had a comparatively high percentage of organic matter, clay, iron and aluminium oxide contents were used for the adsorption studies. The results clearly indicated a decrease in the adsorption capacity of the soils by as much as 75% when organic matter was removed. The other parameters such as clay and iron and aluminium oxides also play an important role in adsorption (57 and 39.8% reduction respectively). It was observed that out of the selected factors organic matter in the soils has the maximum effect regarding the adsorption of p-dichlorobenzene. Since the selected soils contain comparatively more organic matter, clay and iron and aluminium oxides in the selected industrial area, these can be used as sites for dumping hazardous waste, which can be further treated by methods like bioremediation. 相似文献
12.
Geoenvironmental concerns involve unsaturated soils in problems like soil contamination, waste disposal and ground-atmosphere
interactions. This paper deals with the two first points. To tackle geoenvironmental problems in unsaturated soils, it is
necessary to identify experimentally the retention and transfer phenomena that govern the movements of fluids and chemical
species in the unsaturated soil. Some of the experimental techniques used in unsaturated soils can be adapted to face these
problems, but extensions accounting for the various physico-chemical processes involved in soil contamination and waste disposal
are necessary, including temperature effects and the mechanical couplings resulting from the changes in temperature and chemical
concentrations. After an introduction to the geoenvironmental problems that are related to unsaturated soils, the paper presents
a series of experimental developments carried out in relation to retention and transfer properties of water (pure or with
dissolved species), hydrocarbons and gas, also accounting for temperature effects and chemical effects. The techniques presented
are applicable to soil contamination and waste disposal, with a special concern addressed to nuclear waste disposal, in which
the effects of desaturation of the geological barrier together with the unsaturated nature of compacted engineered barriers
appeared to be quite important. 相似文献
13.
Geochemistry of soils along a transect from Central Mexico to the Pacific Coast: A pilot study for continental-scale geochemical mapping 总被引：2，自引：2，他引：0
J.A. Chiprs A. de la Calleja J.I. Tellez F. Jimnez C. Cruz E.G. Guerrero J. Castro M.G. Monroy J.C. Salinas 《Applied Geochemistry》2009,24(8):1416
The Mexican Geological Survey (SGM), the National Institute of Statistics, Geography and Informatics (INEGI) and the Autonomous University of San Luis Potosi (UASLP) have established a multidisciplinary team with the objective of creating a national program of geochemical mapping of soils in Mexico. This is being done as part of the North American Soil Geochemical Landscapes Project in partnership with the US Geological Survey and the Geological Survey of Canada. As the first step, a pilot study was conducted over a transect that extends from the Mexico–US border near Ciudad Juarez in the north to the Pacific Ocean in the south. This pilot transect was conducted in two phases, and this paper presents results from the first phase, which sampled soils at about a 40-km spacing along a 730-km transect beginning in Central Mexico and ending at the Pacific Coast. Samples were collected from the A and C horizons at each site and 60 elements were analyzed. This pilot study demonstrates that geochemical mapping based on a 40-km spacing is adequate to identify broad-scale geochemical patterns. Geologic influence (i.e., soil parent material) was the most important factor influencing the distribution of elements along the transect, followed by the influence of regional mineralization. The study also showed that influence by human activities over the transect is minimal except possibly in large mining districts. A comparison of element abundance in the A horizon with the environmental soil guidelines in Mexico showed that the natural concentrations of the studied soils were lower than the established threshold for soil restoration with the exception of V and As. The former had a median value (75 mg/kg) approximately equal to the value established in Mexico for soil restoration in agricultural and residential lands (78 mg/kg), and the latter had three values higher than the 22 mg/kg threshold for soil restoration in agricultural and residential lands. These cases demonstrate the importance of knowing the national- and regional-scale geochemistry of Mexican soils as a support for the decision-making process, particularly for the proper formulation and application of soil guidelines designed to protect human and ecosystem health. 相似文献
14.
土壤元素地球化学基准是指自然环境中土壤元素正常含量,属于土壤固有的化学组成与结构特征。江苏省现有国土面积约102 600 km2,至2007年已经完成全省1∶250 000多目标区域地球化学调查。按照4 km2采集1个样品、采样深度150～200 cm,16 km2分析测试1个组合样,共获得全省6 127个代表自然环境土壤之样品的52个元素与TOC含量的数据,剔除异常含量数据后,以平均含量代表全省土壤元素地球化学基准值、"基准值±1.5或2倍标准离差"表示元素基准值变化范围,获得了江苏省土壤52个元素及TOC的地球化学基准值,为土壤环境评价等提供了基础资料。结果表明:(1)全省土壤大多数元素含量数据不服从正态分布,但剔除异常数据后对平均含量影响不明显;(2)人为活动因素导致江苏土壤的Cd、Hg、Se、N等元素在地表20 cm以上深度发生显著富集,给建立土壤元素地球化学基准值增添了新的难度;(3)成土母质、土壤成因类型与地貌等差异是影响江苏土壤元素含量分布的基本要素。 相似文献
15.
A. Mohamed 《Environmental Geology》2002,42(8):910-921
This study evaluates the potential use of cement-kiln dust (CKD), a waste product from the cement industry, for enhancing the mechanical as well as the hydraulic properties of soils in arid lands. Stabilized products will play a major role in reducing slope failures, pavement damage and the design of containment barriers for hazardous waste in arid lands. Various tests to determine the different physical properties of the stabilized matrix were conducted and the optimum mixture that produces maximum internal energy and minimum hydraulic conductivity was selected. The effect of soaking and unsoaking of the treated specimens on the mechanical properties was also evaluated. The effect of metal ion concentration and conjugate anions on the resultant hydraulic conductivity was evaluated. The optimum percentage of CKD was calculated by using stress-strain data, Newton's divided difference and Simpson's integration technique. The analyses have shown that 6% by weight of CKD is the optimum mix design, which increases the shear strength and decreases the hydraulic conductivity to less than 10-9 m/s. Therefore, the treated soil could be used as a soil-based barrier layer for containment of hazardous waste. 相似文献
16.
The mobility of Cu2+, Zn2+, Ni2+, and Cd2+ in soils treated with red mud was experimentally studied to explore the feasibility of remediation of smelter-contaminated soils. Red mud samples were collected with the Bayer process (BRM) and confederate process (CRM) in the Aluminous Plant of Guizhou Province. Two farmed soil samples were collected from the Niujiaotang mining area, Guizhou Province, Southwest China. One sample was weakly polluted by fly ash; and the other was polluted severely by waste water from the smelter. For evaluating the potential of remediation, the concentrations of free metal ions and the distributions of metals in the soil were determined. The concentrations of free metal ions were measured by using the Donnan Membrane Technique, and the contributions of soil sorbents to the heavy metals adsorptions were calculated with Equilibrium Calculation of Speciation and Transport (ECOSAT). BRM reduced the concentrations of free metal ions in two kinds of soils, while CRM only favored the decrease of the concentrations of free metal ions in seriously contaminated soils. The experimental data also showed a tendency that the concentrations of free metal ions decreased proportionally with the amount of added red mud, which resulted from the increasing adsorption of heavy metal ions in the form of metal ion hydroxides. 相似文献
17.
土地质量地球化学调查计划是我国继区域化探全国扫面计划之后一个新的国家地球化学填图计划,该计划实施20年来,在支撑土壤环境污染防控、土地资源管理、国家重大立法、精准扶贫等方面做出了重大贡献,显著拓展了地质工作服务链。本文从计划的提出背景、项目的组织实施、主要进展、调查技术的进步和分析测试技术的提高与质量控制方案的完善等方面回顾了该计划的发展历程。从全国耕地地球化学状况、全国省会城市土壤环境质量状况、中国主要淡水湖泊沉积物环境质量状况、中国主要农耕区20年来土壤碳库变化4个方面对调查成果做了全面总结。全方位介绍了调查应用成果在土地管理、土壤污染防治、农业种植结构调整、脱贫攻坚、地方病防治、油气勘查、固体矿产勘查等7个领域中的应用。并在调查技术革新、评价方法创新和调查与研究融合三个方面对土地质量地球化学调查工作的未来发展趋势做了展望。 相似文献
18.
The quantity of the by-product olive cake residue generated in most parts of the Mediterranean countries continues to increase and expected to double in amount within 10–15 years. This increase intensifies the problems associated with the disposal of this by-product. Olive cake residue has a potential for use as a soil stabilizer and large volumes can be beneficially used. This study is directed toward determining if olive cake residue can be utilized to increase the strength and stability of expansive soils which constitute a costly natural hazard to lightweight structures on shallow foundations. A series of laboratory tests using engineering properties, such as Atterberg limits, moisture-density relationship (compaction), swell, unconfined compressive strength were undertaken to evaluate the effectiveness and performance of the olive cake residue as a soil stabilizer. Test results indicate that an addition of only 3% burned olive waste into the soil causes a reduction in plasticity, volume change and an increase in the unconfined compressive strength. However, it was observed that the presence of burned olive waste in the soil greater than 3% caused an increase in the compressibility and a decrease in the unconfined compressive strength. Test results indicate that the use of olive waste in soil stabilization gives greater benefits to the environment than simply disposing of the by-product, olive cake residue. 相似文献
19.
Murat Ayaz Erkutay Tasdemirci Huseyin Yuksel Volkan Aygul 《Arabian Journal of Geosciences》2018,11(22):725
The condition of the ambient air must be continuously checked to detect hazardous gas leakage and ensure the safety of employees in hazardous gas production and storage areas. Detection and elimination of hazardous gas leaks can be done with various complex measurement, safety, and disposal systems. These measurement systems consist of different types of sensor and require control and monitoring system. This leads to high investment and operating costs. In this study, semi-continuous measurement system automation with a single set of sensors working by taking air samples from different points over specific periods has been designed to reduce investment, operation, and maintenance repair costs. In the design, the measurement points are divided into zones and codes in the automation system. Thus, it is aimed to keep a constant record of what the air sample is coming from and what its content is. As a result, it has been determined that it is possible to establish a measurement and automation system similar to existing hazardous gas measurement systems with less investment and operating costs. The proposed automation system has been applied in the industrial storage area. In addition, a cost analysis has been performed and compared with conventional systems. 相似文献
20.
Primary sand and gravel deposits in Britain play an important role in preserving our cultural heritage and are also a valuable aggregate resource. While an understanding of the extrinsic properties of the soil archive (such as pH, redox, groundwater) can provide a firstorder assessment of the potential risk to any archaeologically sensitive deposits, we have very poor definition of spatial variations in the extrinsic properties of soil that influence archaeological preservation at a regional and national scale. Developments in digital geological mapping, remote sensing, and geochemical survey data undertaken by the British Geological Survey (BGS) have, however, significantly extended capabilities in this respect and can potentially be used to provide a primary assessment of the sensitivity of the present soil archive and the potential risk from changes to the soil process on cultural material in areas earmarked for aggregate extraction. Two of the major factors affecting archaeological preservation—soil acidification and groundwater—can be mapped or predicted at scales of better than 1:50,000 across increasingly large parts of the country using a combination of regional hydrogeological, geophysical, and geochemical data. Additional data from site investigations may further refine preservation potential as a function of changes in redox potential and acidity. These data, maps and models can be used to (1) better establish a baseline for archaeological preservation at a regional and national scale and (2) improve our understanding of how the physical and chemical properties of the near surface environment can be managed to sustainably preserve archaeological materials in areas impacted by sand and gravel extraction. © 2009 Wiley Periodicals, Inc. 相似文献