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Impacts of the dumping site on the environment: Case of the Henchir El Yahoudia Site, Tunis, Tunisia
The Henchir El Yahoudia landfill is one among many uncontrolled dumping sites in Tunisia with no bottom liner. It is located at the southeastern edge of Sijoumi Sebkha. The site has been exploited since 1963 until 1994. It constitutes a peculiar case because of its situation, its exploitation mode and the nature of buried wastes. Leachate analysis shows that they are strongly charged with nitrogen (especially ammoniacal and kadjedahl), organic compounds with a high biodegradability and a charge of metallic elements exceeding the Tunisian norm NT 106-002. Sediment analyses show that the highest rate of heavy metals and organic matter coincides with clay-richest layers, characterized by the highest specific-surface values. The percolation of these pollutants until the groundwater between 0.5 and 5 m has provoked a pollution characterized by high rates of organic matter (BOD, COD and nitrogen) and heavy metals. To cite this article: A. Marzougui, A. Ben Mammou, C. R. Geoscience 338 (2006). 相似文献
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Negin Kananizadeh Taghi Ebadi Seyed Alireza Khoshniat Seyed Ehsan Mousavirizi 《洁净——土壤、空气、水》2011,39(7):605-611
This study evaluates the effect of nanoclay on permeability, swelling, compressive strength, and cation exchange capacity of a compacted Kahrizak landfill clay liner. The results show that 4% nanoclay significantly reduces permeability (3 × 10?9 to 7.74 × 10?11 cm/s in neutral, 3.66 × 10?9 to 7.9 × 10?10 cm/s in acidic, and 3.25 × 10?9 to 5.24 × 10?10 cm/s in alkaline condition), and increases compressive strength (by 36.28%) and the percentage of swelling (from 16.67 to 41.82, 23.33 to 45.45, and 15 to 38.18 at pH 7, 4.8, and 9, respectively) compare to raw clay samples. Moreover, the results of cation exchange capacity tests show that adding 4% nanoclay to the Kahrizak clay, permeated with landfill leachate, helps the sample maintain its mono‐valent ions between layers and remains dispersed. The results of SEM and XRD analyses show that by adding nanoclay, nanoclay clusters are formed in the sample; as a result, the interlayer spacing decreases which makes it remain dispersed. XRF analyses also demonstrate that by adding nanoclay to the mixture, the permeability and therefore, the amount of heavy metals which can penetrate into it decreases. The results justify the construction of clay barriers with nanoclay in order to prevent leachate penetration, and consequently reduce the operation costs. 相似文献
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The internal structure and the integrity of the containment walls are aspects of landfill site management that need to be continuously monitored. Monitoring currently involves construction of boreholes and chemical analyses of surface samples which are time-consuming and expensive. The applicability of ground penetrating radar (GPR) as an aid to monitoring these processes has been investigated. GPR surveys have successfully resolved the shallow depth soil and geological structure, identified the structure and history of the waste input, defined the water table in three dimensions and identified leachout breakout points in the impermeable lining of the landfill edges. Integration of the results of GPR surveys with data from surface surveys and boreholes could provide landfill operators, environmental agencies and commercial companies with a cost-effective monitoring methodology and a mechanism for enhancing contaminant migration modelling. 相似文献
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Temporal changes in leachate chemistry of a municipal solid waste landfill cell in Florida,USA 总被引:1,自引:0,他引:1
Evaluation of 12 years of landfill leachate chemical data from a lined cell of municipal waste in south Florida, USA shows an overall declining trend in major ion chemistry. The leachate is dominantly Cl, Na, HCO3 and organic solutes. There are significant short-term variations in concentration that appear to be related to rainfall, rather than fundamental changes to leachate composition. Inorganic parameters related to pH, such as alkalinity, calcium, and magnesium appear to be chemically buffered. Chromium, cobalt, vanadium, zinc, and the metalloid boron display significant short-term co-variance with a decreasing trend. Iron and manganese concentrations increased significantly after capping. Based on the predominance of ammonia, historic methane generation, and increasing trends for iron and manganese after closure, the landfill cell has an anaerobic (reducing) interior environment. The reducing conditions were enhanced by capping and caused the most redox sensitive metals (manganese and iron) to become more mobile. 相似文献
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Long‐term Assessment for the Leachate Release of Heavy Metals from Municipal Solid Waste Incineration Bottom Ash Monofills Municipal solid waste incineration (MSWI) bottom ash was investigated by chemical, mineralogical, and microbiological methods as well as leaching‐ and laboratory lysimeter tests. Compared to geological material bottom ash shows a high content of soluble salts, organic carbon, and heavy metals. The heavy metals are mainly bound in alloys and glas. Addition of oxic and acetic solutions quickly oxigenize the metal‐phases and alloys. Only fixation in newly formed phases like carbonates or hydroxides prevents heavy metal release till pH 7 in case of pH‐reduce. In the long‐term the acid buffer is reduced by the environmental acid input in combination with the release of buffering phases (mostly calcite). Internal acid producing processes like decay of organic matter or oxidation of sulfides are not important for the pH‐decrease. Cu, Ni, and Zn are first released between pH 7 and 6 (mainly Zn) and a second time at pH values below 5 (mainly Cu). Pb is significantly released at pH values below 5, Cr only at pH < 4. Mainly metals, alloys, and the rims of glas are destroyed by leaching. Phases like metal hydroxides (mainly Fe‐phases) or amorphous, water bearing Fe‐Al‐Si‐oxides are finally formed. Long‐term leaching by acetic fluids increases the total availability of heavy metals (except Cr) with increasing time. Kinetic effects including changing of metal binding forms seem to be responsible for this development. Within deposit conditions of limited gas exchange (closed system) the pH of the carbonate buffering zone can drop below pH 7 in case of very strong acid input and quickly cause an enhanced metal release. But in reality such a strong acid input is not to be expected. Calcite will buffer between pH 8 and 7 for a long time. Depending on the environmental conditions (water balance, acidity of rain) and landfill design (compaction, permeability, cover, thickness) it can take hundreds till thousands of years until metal release will start. The long‐term metal release of matter with an acid buffer like carbonates can be approximately determined only by short‐term tests with powder (e.g. pHstatic tests at pH 4). 相似文献
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城市生活垃圾卫生填埋场填土层工程特性及净化机理研究 总被引:3,自引:0,他引:3
张莲花 《地质灾害与环境保护》1999,(Z1)
城市生活垃圾卫生填埋场中,填土层对垃圾淋滤液的渗透阻滞和净化作用具有重要意义。对成都万兴固体废弃物处置场填土料的压实性、渗透性及其相互关系,在大量试验的基础上作了深入探讨并导出关系式。填土层对垃圾淋滤液中污染物的衰减净化,是各种因素综合作用的结果。以工程地质为基础,研究生活垃圾淋滤液中常见离子净化规律和机理,认为土层结构的不同,对淋滤液的净化有一定影响,而这种影响因离子的不同而有不同程度的表现:二价离子交换吸附,引起渗透系数在0.5~1.0个数量级范围内变化;离子的负吸附,表明土层吸附的可逆性;而典型的一价离子NH+4和Cl-的净化规律,可用指数函数表征;有机物的衰减与土的有机碳的含量有关。这些研究成果,为全面研究填埋体结构的合理化设计提供了重要依据。 相似文献
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Landfill is the primary method of waste disposal. The increasing attention focused on the effect of landfill on environment prompts the development of environmental sound landfill system. As the key parts of landfill, the barrier system can provide impermeabilization of leachate and prevent biogas from escaping intotheenvironment. In recent years, the technology pertaining the barrier system developed rapidly. In this paper, new materials used in liners and new concept of barrier construction are reviewed; the mechanisms of leachate through clay liner and geomembrane, the calculation of leaks through liner and the effect of freezing/thaw on liner are discussed. 相似文献