共查询到17条相似文献，搜索用时 401 毫秒
1.
通过实验研究筛选出一种经济可行的用于修复Cr(Ⅵ)污染地下水的PRB反应介质。实验以Cr(Ⅵ)污染地下水为研究对象,选用MB、Fe0、粉煤灰和活性炭4种材料进行PRB介质筛选的静态实验,选取处理效果好且经济的MB作为PRB反应介质进行动态修复实验。结果表明:以MB作为PRB反应介质可以使Cr(Ⅵ)的质量浓度从0.50 mg/L降低到0.05 mg/L以下,达到地下水水质Ⅲ类标准;且MB具有吸附量大、固液分离容易、无解吸、无二次污染等优点。以MB作为PRB反应介质修复Cr(Ⅵ)污染的地下水是可行的。 相似文献
2.
渗透反应格栅修复铬污染地下水的试验研究 总被引：13，自引：0，他引：13
试验用零价铁 (Fe0) 和活性炭作为反应介质,设计渗透反应格栅 (PRB),对六价铬[Cr(Ⅵ)]污染地下水进行了实验室修复研究.试验结果表明:活性炭对 Cr 有一定的吸附作用;Fe0 对 Cr(Ⅵ) 有较强的还原作用;Fe0 和活性炭的协同作用有效地增强了Fe0 PRB 的处理能力;可以使 Cr(Ⅵ) 从 20 mg/L 降低到 0.05 mg/L 以下.冲洗试验表明,Fe0 还原 Cr(Ⅵ) 生成 Cr(Ⅲ),Cr(Ⅲ) 生成 Cr(OH)3 沉淀,而没有随着水体流动而流失到"下游"水体中.实验结果说明 PRB 技术治理 Cr(Ⅵ)污染地下水是可行的. 相似文献
3.
以受尾矿库渗滤液重金属离子Pb2+、Cd2+污染的地下水为研究对象,用天然矿物材料红辉沸石与膨润土作为反应渗透墙(PRB)的活性介质填充材料,试验结果表明,膨润土∶红辉沸石=1∶7,PRB渗透系数处于10-4cm/s数量级且随时间下降最为缓慢;PRB对单一组分Pb2+和单一组分Cd2+去除率分别达99.95%和99.995%;但在双组分PRB体系中,重金属离子Pb2+的存在显著地抑制了PRB对Cd2+的吸附作用,优先选择性吸附顺序是Pb2+Cd2+。 相似文献
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两种废物材料在地下水环境治理中的应用 总被引：2，自引：1，他引：1
实验利用粉煤灰和矿化垃圾两种废物材料作为反应屏障的反应介质用于修复受渗滤液污染的地下水环境。所设计的两个反应器A、B分别填充矿化垃圾和粉煤灰,利用它们的吸附能力、阳离子交换能力以及微生物的作用去除污染质。试验结果表明:A、B两柱COD的去除率最高可达66%和59%,对铵氮的去除率柱A明显优于柱B,最高可达92.7%,并在81%左右保持稳定。另外柱A对硝酸盐氮和亚硝酸盐氮的去除效果也优于柱B。说明矿化垃圾作为反应屏障介质更加经济可行,可以达到以废治废的目的。 相似文献
6.
《地学前缘》2021,(5)
渗透反应格栅(permeable reactive barrier,PRB)在国外被广泛应用于场地尺度的地下水污染修复,因其无须外源动力、不占地面空间、运行成本低等优势在国内受到广泛关注。不同场地水文地质条件、污染物类型、污染羽分布具有差异性,前期场地调查、反应材料的筛选、反应墙尺寸结构的设计对于PRB的有效运行至关重要。本文以PRB修复河南某Cr(Ⅵ)污染场地为例,详细阐述场地调查、材料筛选、材料反应参数确定、PRB结构优化等方面的研究过程及成果,可为后续PRB修复技术的应用提供参考。研究结果表明:PRB修复技术适用于该场地,铸铁与活性炭混合材料为最佳修复材料;反应门长40m(反应材料厚2m,上下游分别为2m厚砾石层),东西两侧隔水墙长为60m的U型漏斗门系统型PRB,可有效捕获并修复污染羽,工程成本远低于连续反应墙式PRB,为该场地修复最优PRB结构类型。 相似文献
7.
渗透反应格栅(permeable reactive barrier,PRB)在国外被广泛应用于场地尺度的地下水污染修复,因其无须外源动力、不占地面空间、运行成本低等优势在国内受到广泛关注。不同场地水文地质条件、污染物类型、污染羽分布具有差异性,前期场地调查、反应材料的筛选、反应墙尺寸结构的设计对于PRB的有效运行至关重要。本文以PRB修复河南某Cr(Ⅵ)污染场地为例,详细阐述场地调查、材料筛选、材料反应参数确定、PRB结构优化等方面的研究过程及成果,可为后续PRB修复技术的应用提供参考。研究结果表明:PRB修复技术适用于该场地,铸铁与活性炭混合材料为最佳修复材料;反应门长40 m(反应材料厚2 m,上下游分别为2 m厚砾石层),东西两侧隔水墙长为60 m的U型漏斗-门系统型PRB,可有效捕获并修复污染羽,工程成本远低于连续反应墙式PRB,为该场地修复最优PRB结构类型。 相似文献
8.
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
9.
修复石油类污染地下水的PRB反应介质研究 总被引：4，自引：0，他引：4
以石油类污染地下水为研究对象,选用颗粒活性炭、草炭土、粒径为1 mm和3 mm的页岩陶粒、泥岩陶粒、高岭土、聚乙烯醇、细砂和白砂等9种材料进行PRB反应介质筛选及其性能研究。筛选实验结果表明,草炭土去除地下水中总石油烃的效果最好;动态吸附实验结果表明,在吸附1 h时,草炭土去除总石油烃已经达到动态平衡;通过热处理改性,草炭土去除石油烃效果得到提高,在130℃、热处理2 h去除石油烃效果最好;颗分后吸附实验结果表明,在粒径2 mm范围内,草炭土吸附效果均十分显著。在此基础上进行吸附石油烃前后草炭土的微观结构观察及理化性质分析。以上研究表明,草炭土作为PRB反应介质处理石油类污染地下水具有良好的应用前景。 相似文献
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11.
At a Cr(VI) contaminated site in Thun, Switzerland, a permeable reactive barrier (PRB) was installed in 2008. Downstream Cr(VI) concentrations did not indicate any sign of its successful operation more than 2 years after PRB installation. The cause for this potential PRB failure was investigated by performing Cr isotope measurements and a multi-tracer experiment. The combination of reactive (Cr isotopes) and non-reactive tracers allowed characterizing the groundwater flow regime in the vicinity of the PRB in detail. In particular, it could be confirmed that most of the Cr(VI) load is currently bypassing the barrier, whereas only a minor Cr(VI) load is flowing through the PRB. Fitting of observed breakthrough curves using a conventional advection dispersion model resulted in average linear flow velocities of 13–15 m/day for the bypassing Cr(VI) load and 4–5 m/day for the Cr(VI) flowing through the barrier. Using a Rayleigh fractionation model a Cr(VI) reduction efficiency of 77–98% was estimated for the Cr(VI) load that is flowing through the barrier. In contrast, a value of 0–23% was estimated for the current overall PRB reduction efficiency. It is concluded that the PRB bypass and the low overall Cr(VI) reduction efficiency are caused by a limited PRB permeability inherited from skin effects that occurred during PRB emplacement. 相似文献
12.
Hexavalent chromium is a soluble, mobile, and highly toxic metal ion in groundwater. Adsorption by permeable reactive barriers (PRBs) with special sorbent is a common method to remove hexavalent chromium. A series of experiments have been performed to remove hexavalent chromium in groundwater under PRB with modified chitosan. Therefore, in this paper, the authors first estimated adsorption characteristics of the modified chitosan in a column test, and then calibrated the PRB adsorption parameters in a sandbox test, and finally designed an optimal width, length, and depth of the PRB with the same reactive media in a three-dimensional aquifer. The results showed that the modified chitosan might be a potential adsorption medium. The design schemes can meet the water quality standard of 0.1 mg/L Cr(VI). Heterogeneity of dispersion is a crucial factor when designing the PRB. Therefore, the design of the PRB structures can be appropriate and serve as reference for groundwater remediation. 相似文献
13.
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
14.
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
15.
As an in situ, simple and passive technology, Permeable Reactive Barrier (PRB) is becoming widely used in groundwater remediation. Based on its definition and development process, the development of PRB can be divided into two stages: The traditional zero-valent iron PRB before 2000 and the PRB composed of novel mixed media after 2000. With the rapid worsening of groundwater pollution, the increasing application of PRB and the rapid development of materials science, the development of PRB technology in future will be mainly focused on the investigation of mixed and novel media, the design of mixed PRBs, the combination of PRB technology with other remediation technology, and the long term monitoring and management of PRB projects. 相似文献
16.
R. Doherty D.H. Phillips K.L. McGeough K.P. Walsh R.M. Kalin 《Environmental Geology》2006,50(1):37-46
A sequential biological permeable reactive barrier (PRB) was determined to be the best option for remediating groundwater that has become contaminated with a wide range of organic contaminants (i.e., benzene, toluene, ethylbenzene, xylene and polyaromatic hydrocarbons), heavy metals (i.e., lead and arsenic), and cyanide at a former manufactured gas plant after 150 years of operation in Portadown, Northern Ireland. The objective of this study was to develop a modified flyash that could be used in the initial cell within a sequential biological PRB to filter complex contaminated groundwater containing ammonium. Flyash modified with lime (CaOH) and alum was subjected to a series of batch tests which investigated the modified cation exchange capacity (CEC) and rate of removal of anions and cations from the solution. These tests showed that a high flyash composition medium (80%) could remove 8.65 mol of ammonium contaminant for every kilogram of medium. The modified CEC procedure ruled out the possibility of cation exchange as the major removal mechanism. The medium could also adsorb anions as well as cations (i.e., Pb and Cr), but not with the same capacity. The initial mechanism for Pb and Cr removal is probably precipitation. This is followed by sorption, which is possibly the only mechanism for the removal of dichromate anions. Scanning electron microscopic analysis revealed very small (<1 μm) cubic highly crystalline precipitates on the flyash, although this new crystalline zeolite growth did not occur rapidly enough to enable productive zeolite formation. Surface area measurements showed that biofilm growth on the medium could be a major factor in the comparative reduction of surface area between real and synthetic contaminant groundwaters. The modified flyash was found to be a highly sorptive granular material that did not inhibit microbiological activity, however, leaching tests revealed that the medium would fail as a long-term barrier material. 相似文献
17.
A laboratory experiment with two sequenced columns was performed as a preliminary study for the installation of a permeable
reactive barrier (PRB) at a site where a mixed ground water contamination exists. The first column contained granular zero
valent iron (ZVI), the second column was filled with granular activated carbon (GAC). Trichloromethane (TCM, 930 μg/l) and
chlorobenzene (MCB, 260 μg/l) were added to the ground water from the site as the main contaminants. Smaller amounts (<60 μg/l)
of benzene, 1,2-dichloroethane, 1,1,2-trichloroethane (1,1,2-TCA), 1,1-dichloroethene (1,1-DCE), trichloroethene (TCE), tetrachloroethene
(PCE), 1,2-dichloropropane (1,2-DCP), bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM), vinyl
chloride and chromate were also added to the water to simulate the complex contamination pattern at the site of interest.
PCE, TCE, 1,1-DCE, DBCM, BDCM, TBM, MCB and chromate were remediated in contact with ZVI, while the remaining contaminants
showed incomplete degradation. A fraction of 8–16.5% TCM was converted to dichloromethane (DCM). Remaining contaminant concentrations
were efficiently sorbed by the GAC until breakthrough of DCM was observed after 1,230 exchanged pore volumes in the GAC. The
results show that the complex mixture of contaminants can be remediated by a sequenced PRB consisting of ZVI and GAC and that
DCM sorption capacity is the critical parameter for the dimensions of the GAC reactor. 相似文献