共查询到19条相似文献，搜索用时 375 毫秒
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在阐述膨润土的矿物学特性、类型及其改性方法（包括酸活化、焙烧、无机盐,有机铵盐）的基础上,探讨了其在废水处理、垃圾填埋场和土壤改良中的应用现状,并以膨润土作为反应介质,COD（化学需氧量）、Cr6+和NH4+为靶污染物,进行垃圾渗滤液对地下水污染的渗透反应格栅（PRB）实验研究,结果表明：pH值和DO（垃圾渗滤液中的溶解氧）对靶污染物的去除效果有一定的影响,且反应介质对COD、Cr6+和NH4+的去除率分别为53%、51%和53%,此结果说明了以膨润土作为PRB的反应介质是可行的. 相似文献
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循环流化床燃烧产生的粉煤灰按不同比例与污水充分混合,其对污水中P的去除率可达90%以上;对COD的去除率为45%左右;对NH3-N的去除效果较差,最高不超过11%。由于粉煤灰含有大量钙,可以与粉煤灰中的磷酸盐形成沉淀,故采用循环流化床产生的粉煤灰可以有效处理含P较高的污水。文章研究了粉煤灰中重金属在污染水中释放规律,如Pb、Cd、Cu、Cr及Ni等,由于粉煤灰与污水浸泡后pH值呈碱性,且污水中含有大量有机物质,使反应体系呈还原状态。因此,粉煤灰中的重金属可以稳定存在,粉煤灰在污水中几乎不释放重金属,所以未加任何处理的粉煤灰在浸泡过程中不会对环境产生重金属污染。为此,粉煤灰可用于井下采空区回填,也可用于路基填充等。由于粉煤灰中少量碱性物质溶于水中,可使地下水pH值升高。 相似文献
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垃圾渗滤液污染晕中污染物的衰减规律研究 总被引：4，自引：3，他引：1
通过实验室土柱模拟实验,研究垃圾渗滤液污染晕中不同污染物在空间和时间上的迁移转化规律和生物地球化学作用机理。实验结果表明：渗滤液污染晕中,TOC浓度随距离增加而降低,其初期去除率为99.87%。随着时间的延长,TOC浓度升高,末期去除率仅为55.21%,而且其在地下环境中的迁移能力较强;铵氮空间上的变化规律在初期与TOC相似,其去除率达99.58%,但后期其浓度随距离的增加呈先升高后降低的变化趋势。随着时间的延长,铵氮浓度不断升高,但其迁移能力不及TOC,末期去除率仍高达90.21%。 相似文献
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土壤污染日益严重,其中作为土壤污染类型之一的放射性核素污染已引起广泛关注。土壤中的部分微生物可以矿化 固结重金属离子,从而达到去除重金属离子的目的。本文实验对从土壤中分离的1株碳酸盐矿化菌的特性及其对Sr2+的矿化 结果进行研究,发现该菌对1.0g/L和0.5g/L模拟核素Sr2+的去除率可达98%和99%。扫描电子显微镜（SEM）、能谱分析 （EDS）、X射线衍射（XRD） 、傅里叶变换红外光谱（FTIR）等结果显示,矿化产物为碳酸锶。可见,利用碳酸盐矿化菌 治理土壤中放射性核素Sr2+污染具有可行性,该方法将会有一定应用前景。 相似文献
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本文利用胶质芽孢杆菌(Bacillus mucilaginosus)和黑曲霉(Aspergillus niger)处理铜-苯酚(简称铜-酚)和镉-苯酚(简称镉-酚)这类有机-无机复合污染模拟废水,采用胶质芽孢杆菌和黑曲霉分别单独、联合或先后处理等5种方式,探讨了这两类菌体对复合污染模拟废水的处理效果及优化方法。结果表明,微生物对铜-酚废水的处理效果优于对镉-酚废水。对于铜-酚废水的处理表明,当废水中苯酚浓度为50~200 mg/L时,去除率可达80%以上,最高可达94.65%,其中铜的去除率较苯酚低;当模拟废水中铜浓度为30 mg/L时,可达最高去除率(60.02%)。微生物对镉-酚废水的处理表明,当废水中镉离子浓度为4 mg/L时,最高去除率为58.44%,苯酚的去除率一直保持在30%左右。 相似文献
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《地学前缘》2021,(5)
土壤含水层处理系统(soil aquifer treatment,SAT)是一种重要的人工回灌地下水方式。以再生水为回灌水源时,水中含有的"三氮"可能会对回灌区地下水造成污染风险。研究各种因素对在SAT中去除再生水中"三氮"的影响具有重要意义。本研究中,通过高200cm、内径50cm土柱试验,研究了SAT系统中粒径、干湿比(落干期与淹水期的比值)、在系统表层增加生物炭及渗透流速对实际再生水"三氮"去除效果的影响。结果表明,在干湿比1∶1条件下,实际河道细砂和中细砂柱底部出水中NH_4-N平均去除率分别为73%和66%,去除机理主要为吸附和硝化作用,NO_2-N基本被去除。系统中硝化作用导致NO_3-N浓度升高,出水中NO_3-N浓度平均增长了3.0%～4.1%。在深度115cm以上,中细砂柱内比细砂柱内的硝化作用更强,这导致了更高的NH_4-N去除率和更低的NO_3-N去除率。延长落干期后(干湿比3∶1),系统具有了更强的复氧能力,促进了硝化作用,使得NH_4-N的平均去除率提高了20%,而NO_3-N的降低了3%～4%,增加了NO_3-N污染风险。在中细砂层添加5%重量生物炭后,吸附性能增强,使其对NH_4-N平均去除率增加了20%～32%,但对NO_3-N影响不明显。渗透流速与NH_4-N的去除和NO_3-N的增加均呈负相关。综合分析可得出,影响SAT系统去除"三氮"的最主要因素是干湿比和渗透流速,在回补水源中NH_4-N浓度较高时,可考虑在SAT系统表层添加生物炭以增强其去除效果。 相似文献
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土壤含水层处理系统(soil aquifer treatment,SAT)是一种重要的人工回灌地下水方式。以再生水为回灌水源时,水中含有的“三氮”可能会对回灌区地下水造成污染风险。研究各种因素对在SAT中去除再生水中“三氮”的影响具有重要意义。本研究中,通过高200 cm、内径50 cm土柱试验,研究了SAT系统中粒径、干湿比(落干期与淹水期的比值)、在系统表层增加生物炭及渗透流速对实际再生水“三氮”去除效果的影响。结果表明,在干湿比1∶1条件下,实际河道细砂和中细砂柱底部出水中NH4-N平均去除率分别为73%和66%,去除机理主要为吸附和硝化作用,NO2-N基本被去除。系统中硝化作用导致NO3-N浓度升高,出水中NO3-N浓度平均增长了3.0%4.1%。在深度115 cm以上, 中细砂柱内比细砂柱内的硝化作用更强,这导致了更高的NH4-N去除率和更低的NO3-N去除率。延长落干期后(干湿比3∶1),系统具有了更强的复氧能力,促进了硝化作用,使得NH4-N的平均去除率提高了20%,而NO3-N的降低了3%4%,增加了NO3-N污染风险。在中细砂层添加5%重量生物炭后,吸附性能增强,使其对NH4-N平均去除率增加了20%32%,但对NO3-N影响不明显。渗透流速与NH4-N的去除和NO3-N的增加均呈负相关。综合分析可得出,影响SAT系统去除“三氮”的最主要因素是干湿比和渗透流速,在回补水源中NH4-N浓度较高时,可考虑在SAT系统表层添加生物炭以增强其去除效果。 相似文献
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Evaluation of bagasse ash treated lateritic soil as a potential barrier material in waste containment application 总被引：1，自引：0，他引：1
Adrian O. Eberemu 《Acta Geotechnica》2013,8(4):407-421
Laboratory tests were conducted on a reddish-brown lateritic soil treated with up to 12 % bagasse ash to assess its suitability in waste containment barriers applications. Soil samples were prepared using four compaction energies (i.e. reduced Proctor, standard Proctor, West African Standard or ‘intermediate’ and modified Proctor) at ?2, 0, 2 and 4 % moulding water content of the optimum moisture content (OMC). Index properties, hydraulic conductivity (k), volumetric shrinkage and unconfined compressive strength (UCS) tests were performed. Overall acceptable zones under which the material is suitable as a barrier material were obtained. Results recorded showed improved index properties; hydraulic conductivity and UCS with bagasse ash treatment up to 8 % at the OMC. Volumetric shrinkage strain increased with higher bagasse ash treatment. Based on the overall acceptable zone obtained, an 8 % optimal bagasse ash treatment of the natural lateritic soil makes it suitable for use in waste containment barrier application. 相似文献
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Alexandra N. Golab Mark A. Peterson Buddhima Indraratna 《Environmental Earth Sciences》2009,59(1):241-254
The Shoalhaven region of NSW experiences environmental acidification due to acid sulphate soils (ASS). In order to trial an
environmental engineering solution to groundwater remediation involving a permeable reactive barrier (PRB), comprehensive
site characterisation and laboratory-based batch and column tests of reactive materials were conducted. The PRB is designed
to perform in situ remediation of the acidic groundwater (pH 3) that is generated in ASS. Twenty-five alkaline reactive materials
have been tested for suitability for the barrier, with an emphasis on waste materials, including waste concrete, limestone,
calcite-bearing zeolitic breccia, blast furnace slag and oyster shells. Following three phases of batch tests, two waste materials
(waste concrete and oyster shells) were chosen for column tests that simulate flow conditions through the barrier and using
acidic water from the field site (pH 3). Both waste materials successfully treated with the acidic water, for example, after
300 pore volumes, the oyster shells still neutralised the water (pH 7). 相似文献
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铁屑粉煤灰微电解法预处理印染废水的研究 总被引：6，自引：3，他引：6
依据微电解的基本原理,采用铁屑粉煤灰对印染废水进行预处理。通过实验确定了影响因素和运行参数,即进水pH值为2.5~3.5,沉淀时pH值为8~8.5,反应时间为1h左右,粉煤灰/铁屑为2.0~3.0。印染废水的CODcr去除率和脱色率分别达到80%和92%以上。 相似文献
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Reactive mixtures to be used in a permeable reactive barrier (PRB) for the treatment of low quality groundwater derived from a mine waste rock storage site were evaluated. Low pH drainage water from the site contained high concentrations of sulfate and dissolved metals, including Al, Co, Ni, and Zn. Column experiments were conducted to evaluate whether mixtures containing either peat moss (as an organic carbon source) or a mixture of peat moss and granular zero-valent iron (ZVI) filings, in addition to small amounts of lime and/or limestone, were suitable treatment materials for removing these metals from the water. The experimental results showed that the mixtures promote bacterially-mediated sulfate reduction and metal removal by precipitation of metal sulfides, metal carbonate/hydroxide precipitation, and adsorption under relatively high pH conditions (pH of 7–8). Both reactive mixtures removed influent dissolved metals to near or below the limit of detection in the effluent throughout the experiment; however, influent-level concentrations of the metals of interest gradually moved through the column containing peat alone, as the pH neutralizing ability in the mixture was consumed. In contrast, the column containing both peat and ZVI showed very little breakthrough of the influent metals, suggesting that the longevity of the mixture including ZVI will be much longer than the mixture containing peat alone. The results show that both reactive mixtures should be effective in a PRB installation as long as neutral pH conditions and microbial activity are maintained. The cost to performance ratio of the two reactive mixtures will be a key factor in determining which mixture is best suited for a particular site. 相似文献
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Compacted clay can minimize infiltration of liquid into waste or control the release of contaminated liquids to the surrounding soils and groundwater. Compacted lateritic soil treated with up to 12 % bagasse ash and municipal solid waste (MSW) leachate sourced from a domestic waste land fill were used in diffusion test studies to access the diffusion characteristics of some inorganic species present in the municipal solid waste leachate. Diffusion set-up were prepared containing 0, 4, 8 and 12 % bagasse ash—soil mixes compacted at 2 % wet of optimum using the modified proctor effort. The set up was saturated with water for 30 days before the introduction of MSW leachate and initiation of diffusion test for another 90 days. After diffusion testing, water content within the soil column showed a decrease with depth. Diffusion test results generally showed that diffusion is an active means of transport of chemical species even at very low flow rates in the compacted soil-bagasse ash mixes, and the effective diffusion coefficient is affected by bagasse ash. The pore fluid concentration profile for the various chemical species tested showed that the compacted soil-bagasse ash mix has the capacity to attenuate Ca2+, Pb2+ and Cr3+ ions. 相似文献
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Hydraulic Conductivity Tests for Evaluating Compatibility of Lateritic Soil—Fly Ash Mixtures with Municipal Waste Leachate 总被引：1，自引：1，他引：0
Agapitus Ahamefule Amadi 《Geotechnical and Geological Engineering》2011,29(3):259-265
Long term competent performance of liner systems is a critical issue in the design and construction of waste repositories
due to adverse interactions associated with leachate generated by wastes. This study was conducted to verify the efficacy
of fly ash stabilization in enhancing compatibility between lateritic soil and municipal waste leachate. Applications investigated
include soil mixtures containing 0, 5, 10, 15, and 20% fly ash compacted at approximately 2% wet of optimum moisture content
with modified proctor energy. Baseline hydraulic conductivity was first established at every level of fly ash content by permeating
soil mixtures with tap water before permeation with leachate in a compaction mould permeameter using the falling head test
method. Results show that the trend in hydraulic conductivity of specimen containing 0% fly ash was characterized by a gradual
but erratic decrease which may suggests partial entry of the leachate cations into the double layer. Conversely, specimens
containing fly ash showed a general trend consisting of an initial drop in k (up to an order of magnitude) that was followed
by slight decrease sustained until k stabilized and later terminated. Above 10% fly ash content, the relatively high values
of k observed was not connected with the reactivity of the soil mixtures with leachate, rather it may be attributed to excessive
fly ash content that altered their textural and hydraulic properties. The result of this study is potentially significant
in the assessment of fly ash as a compatibility enhancing agent which can be admixed in barrier materials that are susceptible
to adverse reactions with the liquid to be contained. 相似文献
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包气带作为防止地下水硝酸盐污染的天然屏障,其反硝化效果通常受到碳源的限制。针对地下水硝酸盐污染防治技术现状,本文采用Ca(OH)2处理的玉米芯作为反硝化的碳源材料,构建包气带强化反应层,用响应曲面法研究硝酸盐浓度、含水量和温度的交互作用对脱氮性能影响,并用硝态氮去除率、亚硝态氮累积、pH值变化以及溶解性有机碳(dissolved organic carbon, DOC)淋失通量综合评价脱氮性能,最后采用高通量测序揭示脱氮层中微生物变化。研究结果表明:温度、含水量以及温度和含水量交互作用对硝态氮去除率影响显著,其中温度是反硝化过程中最关键的因素;系统运行74天后,硝态氮去除率达到50%,亚硝态氮累积量(以N计)大多低于3 mg/L,pH值维持在7.0左右,DOC淋失通量(以C计)介于0.10.2 mg/(cm2·d);高通量测序发现,脱氮层中微生物的丰富度降低,而与反硝化和碳分解有关的微生物相对丰度提高,在碳源的刺激下微生物向有利于脱氮的方向演变。 相似文献
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WuYaoguo WangHui ZhangWencun SunWeijian 《中国地质大学学报(英文版)》2005,16(2):183-188
INTRODUCTION Riverbankfiltration(RBF)isaprocessbywhich surfacewaterissubjectedtogroundpassagebeforebe ingcollectedandusedasadrinkingwatersource(His cockandGrischek,2002;Rayetal.,2002;Doussanet al.,1997).Duringinfiltrationandtravelthroughthe riverbedandaquifersediments,surfacewaterissubjec tedtoacombinationofphysical,chemical,andbiologi calprocessesthatcansignificantlyimprovetherawwa terquality(HiscockandGrischek,2002).Thus,RBF hasbeenusedasapretreatedmethodtoimprovedrink ingwate… 相似文献
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The unintended release of coal ash to the environment is a concern due to the enrichment of contaminants such as arsenic (As) and selenium (Se) in this solid waste material. Current risk assessments of coal ash disposal focus on pH as the primary driver of leaching from coal ash. However, redox speciation of As and Se is a major factor for their mobilization potential and has received much less attention for risk assessments, particularly in disposal scenarios where coal ash will likely be exposed to microbially-driven redox gradients. The aim of this study was to demonstrate the differences of aerobic and anaerobic conditions for the leaching of As and Se from coal ash. Batch sediment-ash slurry microcosms were performed to mimic an ash spill scenario and were monitored for changes in As and Se speciation and mobilization potential. The results showed that the dissolved As concentrations were up to 50 times greater in the anaerobic microcosms relative to the aerobic microcosms during the two week incubation. This trend was consistent with As redox speciation determined by X-ray absorption spectroscopy, which indicated that 55% of the As in the solid phase at the end of the experiment was present as As(III) (a more leachable form of arsenic relative to As(V)). In the aerobic microcosms, only 13% of the As was As(III) and the rest was As(V). More than half of the Se was present as Se(IV) in the original fly ash and in the aerobic microcosms, while in the anaerobic microcosms Se was gradually transformed to less soluble Se(0) species. Likewise, dissolved Se concentrations were up to 25 times greater in the aerobic microcosms relative to anaerobic conditions. While the overall observations of As and Se mobilization potential from coal ash were consistent with expectations for aqueous and solid phase speciation of these elements, the findings directly show the relevance of these processes for coal ash disposal. These results highlight the need to select appropriate environmental parameters to include in risk assessments as well as provide potential geochemical monitoring tools through the use of dissolved Se/As ratios to determine the redox conditions of ash storage and spill sites. 相似文献