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1.
填埋场粘性土防渗层中强化微生物对垃圾污染物的净化作用 总被引：3，自引：0，他引：3
如何铺设价廉物关的防渗层,又不需对垃圾渗滤液进行处理,达到环保效果好、成本低的目的,是填埋场防渗衬垫铺设所追求的,但由于科学理论及技术条件的限制,这个目的一直没有达到。通过添加营养菌液强化厌氧微生物对污染物的净化作用,在实验室用土柱进行模拟实验及天然的土柱淋滤净化对比实验,研究了粘性土垫层土中添加营养菌液后,厌氧微生物对垃圾污染物的净化能力的变化,得出了加入厌氧微生物菌液后,可显著地提高微生物在土中对垃圾污染物的净化能力的结论。这为开发价廉物美的垃圾场防渗衬垫打开了思路,为有污染问题的垃圾场提供了一种用微生物治理的方法。 相似文献
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如何铺设价廉物美的防渗层，又不需对垃圾渗滤液进行处理，达到环保效果好、成本低的目的，是填埋场防渗衬垫铺设所追求的，但由于科学理论及技术条件的限制，这个目的一直没有达到。通过添加营养菌液强化厌氧微生物对污染物的净化作用，在实验室用土柱进行模拟实验及天然的土柱淋滤净化对比实验，研究了粘性土垫层土中添加营养菌液后，厌氧微生物对垃圾污染物的净化能力的变化，得出了加入厌氧微生物菌液后，可显著地提高微生物在土中对垃圾污染物的净化能力的结论。这为开发价廉物美的垃圾场防渗衬垫打开了思路，为有污染问题的垃圾场提供了一种用微生物治理的方法。 相似文献
3.
岳普湖乡镇干渠作为岳普湖县的重要输水干渠,其对岳普湖县的水资源供应,农作物生长、区域内农牧民的收入水平有直接的影响。从岳普湖地区的水文地质环境、防渗施工实际出发,对岳普湖乡镇干渠下游的防渗工程进行设计规划,提出在渠道土方工程、碎石垫层铺筑、土工膜铺设、现浇砼施工等施工方案,在施工中注意节能、水土保持、环境保护。 相似文献
4.
成都市"府南河"水环境治理问题的建议 总被引：3，自引：0，他引：3
对成都市一号工程——“府南河”水环境严重失衡的本质问题进行了深入剖析，并提出科学的防治理念是控污的根本，截污、治污是关键，引流冲污是缓解。 相似文献
5.
渗透特性是表征黏性土层防渗能力及防污性能的关键控制因素,黏土衬垫渗透系数的正确选择对保证垫层的防污效果具有极其重要的意义。采用柔性壁渗透仪,通过室内试验研究了混合重金属离子共存情况下侵蚀饱和黏性土的渗透特性变化规律。试验结果表明,将可溶性铜、铬离子混合与铜、锰离子混合溶液作为渗液,黏性土渗透性均随着掺入离子浓度比例的增大而逐渐增强,且相同试验条件下,铜、铬离子混合溶液作为渗液测得的黏土渗透系数值大于铜、锰离子混合溶液作为渗液测得的渗透系数值。混合重金属离子的存在削弱了黏土垫层作为工程防污屏障服役的能力,并对黏土层的水力传导性起到了劣化作用。试验土样微观结构分析表明,渗液特性的改变影响了土样内部的微观结构,随着渗液混合离子质量比的增大,土样中出现了凝聚体且有效输运孔隙通道增大,与宏观渗透特性的变化规律相吻合。研究结果能够为有效评估黏土防污屏障的防渗隔污能力及研究堆场渗液在黏土垫层中的运移机制提供参考。 相似文献
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7.
针对吹填土地基水平排水砂垫层铺设深度优化问题,建立了初始孔压非均布下含砂垫层地基的一维固结模型,利用有限Fourier正弦变换法得出了超静孔压和地基整体平均固结度的解答并通过退化验证了解答的正确性。采用二分法分析了砂垫层的最优铺设深度随时间的演化规律,给出了砂垫层最优铺设深度与时间的关系图。研究表明：在固结初期,砂垫层宜放置在土中初始超静孔压较大的位置;在固结后期,砂垫层的最优设置深度为土体厚度的2/3（单面排水）或者1/2（双面排水）的位置。以预压地基平均固结度达到90%所需时间最短为例,当初始孔压倒三角形、正三角形与梯形分布时,单面排水条件下,应分别在0.52、0.72、0.62倍地基土深度处设置砂垫层;双面排水条件下,应分别在0.42、0.58、0.46倍地基土深度处设置砂垫层。最后通过算例分析了当地基土中砂垫层采用最优铺设深度时,与在中间位置铺设砂垫层、不设砂垫层的情况分别进行对比,当时间因子取0.09时,地基土平均固结度分别提高6%和54%。 相似文献
8.
《岩土力学》2018,(Z2)
填埋场底部黏土垫层特性对其长期防渗隔污服役性能的有效发挥具有极其重要的作用。针对实际堆场中黏土屏障呈现出的高饱和状态,将液相(孔隙水)与气相(闭塞气泡)视为混合流体,通过分别建立土体应力平衡方程、混合流体质量守恒方程及溶质质量守恒方程,综合考虑土颗粒-孔隙流体-溶质间的相互作用机制,推导得到了高饱和度条件下,溶质在黏土防渗层中运移的水-力-化全耦合模型,能够实现多物理场耦合作用时土层变形量、混合流体压力及溶质溶度随时空分布的直接精确求解。采用多场耦合有限元分析软件COMSOL对所建模型开展数值模拟,结果表明,模型结果与Peters所得结果吻合较好;黏土垫层中可压缩性气体的存在延缓了超孔隙流体压力的消散,加大了土层的沉降量,对溶质在防渗黏土层中的运移进程起到了显著的阻滞效果。 相似文献
9.
袖阀管法灌浆施工质量控制 总被引：1，自引：0，他引：1
在长沙市第一污水处理厂扩建工程截污干管地基防渗灌浆工程中,采用了袖阀管灌浆法施工工艺,根据其工艺流程,主要对成孔、套壳料配方及浇注、灌浆材料以及灌浆过程等关键工序进行质量控制,并在灌浆施工过程中对所遇到的不同特殊情况采取了不同的处理方法,其工程防渗加固质量完全满足设计要求。这也表明袖阀管灌浆法适用于粘土、粉细砂砾等松散地层中的劈裂灌浆施工。 相似文献
10.
藁城县水利局,八四年大力推广塑料薄膜田间垄沟防渗技术,全县铺设塑料薄膜防渗垄沟65万米,取得了较好的防渗效果。塑料薄膜防渗垄沟是采用厚度为0.015毫米的塑料薄膜——聚乙烯薄膜(简称为地膜),在机井主干垄沟表土以下20—30厘米处铺设。用塑料薄膜做为防渗材料,一般适用于 相似文献
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G. Resmi Santosh G. Thampi S. Chandrakaran 《Journal of the Geological Society of India》2011,77(1):42-46
Clay liners are widely used as barriers to arrest the migration of pollutants. These liners are subjected to leaching of various
chemicals and hazardous wastes. Migration of heavy metals through the liner material may lead to changes in the soil properties
and this, in turn, may affect the performance of liners. In this paper, the change in index and engineering properties of
clayey soil due to migration of lead is presented. Pronounced changes in soil properties are noticed when the soil is contaminated
with high concentrations of lead. The findings from the present study are important while designing liners in landfills used
for containment of pollution due to heavy metals and hazardous wastes. 相似文献
13.
For materials of very low hydraulic conductivity used in the landfill liner systems, e.g., natural clay liners, soil-cement liners, etc., diffusion characteristics should be evaluated, as the transport mechanism of contaminant through them is diffusion controlled. Studies on the diffusion characteristics of the hardened liner materials, such as the soil cement, are relatively few compared with those of clayey soils. In this paper, diffusive characteristics of hardened liner materials (HLMs) applied to the liner system of Sudokwon Metropolitan Landfill in Korea, were studied. Laboratory pure diffusion column tests in the pure- and the advection-diffusion status were performed for the chemicals, NaCl, KCl, and CaCl2. To evaluate the diffusion coefficient of a HLMs system, a one-dimensional numerical transport program was developed for use in a multi-layered HLMs system. The range of dispersion coefficients of advection diffusion column tests was a little narrower than that of diffusion coefficients of pure diffusion tests, although the two coefficients were quite close. The effective diffusion coefficients of chloride ions of a HLMs were about a half of those in clayey soil due to the high density by compaction and curing. Diffusion coefficients of chloride ions in this study were correlated closely with hydraulic conductivities of the materials tested and were consistent with work in the literature. 相似文献
14.
Experiment simulation study on removal mechanism of BTEX in using river filtration system 总被引：1，自引：1，他引：0
River filtration system is a natural purification process to remove the pollutants in river water and make use of surface water. In this study, a series of experiments were set up with soil column test and static adsorption experiments to simulate the environmental behaviors of BTEX in the river filtration system. It was found that the environmental behaviors of BTEX in the river filtration system included adsorption and microbial degradation. Among the four components of BTEX used in the experiments, the removal rate of xylene was the highest, ethyl-benzene was second, toluene was third, and that of benzene was the lowest. The stability of the structure of benzene was the major contributor for the relatively lower degradation efficiency, and the low removal rate of toluene was due to the impact of adsorption on degradation. By comparison of the results of soil column test and static adsorption experiments, it was found that the soil–water partition coefficient K d of each component of BTEX was higher, the degradation ratio was lower. Compared with the previous study, the results of this experiment showed that when the initial concentration of the each component of BTEX reached 80 mg/L, the mixed pollution of BTEX could be removed by the river filtration system efficiently, and the average removal rate could be over 65 %. As a natural purification, river filtration system could efficiently remove the BTEX mixed pollution in a quite high concentration and protect the ground water from being contaminated. However, its purification efficiency was limited in a certain time range and concentration. It was shown in the later stage of the leaching experiment that the exudation concentration of BTEX increased, at the same time both the concentrations of the two electron acceptors increased to about the initial concentration and kept stable state until the end of the experiment, which revealed that due to accumulation of the concentration of BTEX in the soil column, the microbial activity was inhibited and then the denitrification and sulfate reduction terminated. When the adsorption saturation was achieved and microbial activity was inhibited, BTEX contamination would penetrate through the unsaturated zone and threaten the security of the ground water. 相似文献
15.
Effect of gravel content on creep behavior of clayey soil at residual state: implication for its role in slow-moving landslides 总被引：2，自引：1，他引：1
Soil creep is mostly manifested in slow-moving landslides. It is often the case for active slow-moving landslide with slip zone comprising clayey soil where creep would develop in the residual condition. If gravel is presented in clayey soil, this will have considerable impact on creep behavior of clayey soil. However, knowledge about creep behavior of the clayey soil containing gravel particles is scarce. This paper discusses creep behavior of natural clayey soil with gravel at residual state through a series of creep shear tests. Soil samples for this testing program were collected from the slip zones of two large slow-moving landslides in China. The collected soil samples consisted of clayey soil containing various amounts of gravel particles. The test results show that the soil specimens underwent two different creep patterns. An attenuating creep pattern was observed when the soil specimens were subjected to creep stress less than the residual strength, and a creep with increasing strain rate, or a nonattenuating creep pattern, with no evident secondary creep was noted when creep stress was intestinally increased to a level slightly greater than the residual strength. The creep patterns of clayey soil with gravel at the residual state observed in this study were noted to be very consistent with those of the gravel-free clayey soil reported in Bhat et al. (Int J Geomater 1(1):39–43, 2011, Nat Hazards 69(3):2161–2178, 2013) and Di Miao et al. (Eng Geol 162:53–66, 2013). This gives an indication that creep patterns of clayey soils with and without gravel at the residual state are essentially the same, or in other words, that the presence of gravel does not change the creep pattern of clayey soil. However, the test results in this study illustrate that the presence of gravel does have a notable effect on creep behavior of clayey soil. Specifically, the creep stress leading to creep failure of clayey soil and the minimum ratio of the creep stress to residual strength (RCSR) increased with gravel content, and the displacement until the tertiary creep was also larger in samples containing more gravel particles. It is postulated that creep behavior of clayey soil at the residual state in this study and its relationship with gravel content may be related to strength recovery and crushing of gravel-sized particles during creep. 相似文献
16.
水化学迁移率是反映污染质在水-土孔隙介质中迁移锋面速度的参数,参数值的大小与土壤介质性质、水流状态、污染物质的物理化学性质有关。利用淋滤土柱的动态平衡试验法,模拟自然降雨入渗条件下,石油类污染物在吉林油田区包气带土层中的迁移转化过程。试验结果表明,其水化学迁移过程可分为淋溶阶段、吸附阶段和平衡阶段;微生物分解作用比较弱;不同厚度土层的淋滤液浓度衰减曲线趋势极为相似。考虑室内实验与野外自然环境之间存在的尺度效应,合理确定了阻滞因子、水化学迁移率。 相似文献
17.
河流渗滤系统对入渗的地表水有一定的净化作用,过去人们很少从理论上研究河流渗滤系统对污染河水的净化作用。本文采用室内土柱实验装置来模拟渭河渗滤系统,研究了硝态氮污染的河水在该系统中的环境行为及净化机制,其环境行为主要为反硝化作用。其净化程度与该渗滤系统的渗滤介质有关,如果渗滤介质为粘土,其净化率达到100%。若介质为粗砂粒物质,其净化程度较低。 相似文献
18.
Composite landfill liner design with Ankara clay, Turkey 总被引：1，自引：0，他引：1
This study presents an overview of the geotechnical properties of the clayey soils, referred to as Ankara clay, at two sites of the Ankara region in an attempt to design a landfill profile composed of a high density polyethylene (HDPE) geomembrane/clay composite liner through the Hydrologic Evaluation of Landfill Performance (HELP) model and the Water Balance Method. The geotechnical properties of the landfill layers along with the water balance factors (i.e., evapotranspiration, precipitation, temperature, etc.) were assessed to determine the height of the water-saturated zone in the refuse above the composite liner for landfill design. The cumulative expected leakage rates through the composite liner constructed with compacted Ankara clay were related quantitatively to the cumulative average leachate head. The results of this investigation show that the leakage rates through the composite liner are within tolerable limits. 相似文献
19.
In order to assess the geological environment impact of a city landfill by the Yangtze River, soils from different depths in the dumpsite were sampled and analyzed. It was found that pollutants content at the site was distinctly higher than that in nearby environments. The content of heavy metals, such as Cd, Hg, As, Pb and Cu, reduces as depth increases; the content of elements F, Cl and N is the contrary. Pollutants migration driven by underground water flow was analyzed, considering the hydro-geological conditions of the site. It is believed that, due to leaching after rainfall infiltration, pollutants in the garbage layer migrates deeper, the cohesive soil in the underlying surface prevents them from spreading to the deeper aquifer; additionally, the high pressure tolerance of the deep groundwater is a key factor in preventing pollutants from entering the aquifer. Furthermore, human control has reduced the annual fluctuation range of water level in nearby rivers, weakening the hydrodynamic relations with phreatic water, and thus reducing the spreading of pollutants to nearby surface waters. 相似文献
20.
In order to assess the geological environment impact of a city landfill by the Yangtze River, soils from different depths in the dumpsite were sampled and analyzed. It was found that pollutants content at the site was distinctly higher than that in nearby environments. The content of heavy metals, such as Cd, Hg, As, Pb and Cu, reduces as depth increases; the content of elements F, Cl and N is the contrary. Pollutants migration driven by underground water flow was analyzed, considering the hydro-geological conditions of the site. It is believed that, due to leaching after rainfall infiltration, pollutants in the garbage layer migrates deeper, the cohesive soil in the underlying surface prevents them from spreading to the deeper aquifer; additionally, the high pressure tolerance of the deep groundwater is a key factor in preventing pollutants from entering the aquifer. Furthermore, human control has reduced the annual fluctuation range of water level in nearby rivers, weakening the hydrodynamic relations with phreatic water, and thus reducing the spreading of pollutants to nearby surface waters. 相似文献