北京市某垃圾填埋场周边地下水质分析研究

本文通过对北京市某垃圾填埋场所在区域地下水水位及水质进行监测,分析垃圾填埋场周边地下水污染状况,结合所在区域地质环境条件,对地下水的污染趋势进行分析,并对垃圾填埋场设计、运行中可能出现的问题提出建议。     

城市垃圾填埋场气体泄漏扩散规律研究

垃圾填埋场内部会产生各种各样的次生物质,其中以甲烷和二氧化碳为主,甲烷发生泄漏扩散引起的火灾爆炸风险极大。为了避免或减少此类安全事故的发生,以北京某城市生活垃圾填埋场为研究对象,监测泄漏气体点位在覆盖膜下泄漏的实际情况,并建立相应三维模型,采用Fluent软件对填埋气在大气中的泄漏扩散过程进行模拟。结果表明：在垃圾填埋场中集气汇总处、堆体边坡处最易发生泄漏,在标准状态下爆炸危险区域以泄漏源为中心径向距离0.5 m,纵向距离3.8 m内呈正态分布,且风速与气体扩散的径向距离成正比、纵向距离成反比。这为城市垃圾填埋场气体泄漏事故应急对策的制定及气体监测点的布置提供了理论依据。     

某垃圾填埋场中污染物迁移及阻滞研究

基于对流-弥散方程及工程屏障对重金属污染物的阻滞作用,以Cu~(2+)为某垃圾填埋场金属离子代表,通过数值模拟的方法研究了该垃圾填埋场中重金属污染的迁移及工程屏障对其阻滞作用。研究结果表明:垃圾填埋场中重金属污染物Cu~(2+)在研究区域发生显著迁移;分别计算运营365d后、3650d后Cu~(2+)的迁移情况,表明随着运营时间的延长区域内浓度变大,存在明显的浓度累积作用;设置厚度为1.0m工程屏障后,浓度明显减小,阻滞效果在96.6%以上。厚度分别为0.2、0.5和1.0m的工程屏障最大阻滞效率分别为65.2%、83.6%和96.6%;厚度仅为0.2m的工程屏障在运营400d左右后开始阻滞失效。研究结果揭示了工程屏障墙的施工厚度在垃圾填埋场运营中的重要作用。     

非正规垃圾填埋场垃圾体量的专项勘查探讨

北京市非正规垃圾填埋场分布广泛,不仅影响北京市市容环境卫生,还给居民生活用水构成极大隐患.如果不能准确查明其污染状态、规模,那么针对性的治理工作就难以开展.为满足非正规垃圾填埋场后续治理、设计的需求,迫切需要对上述非正规垃圾填埋场进行垃圾体量的专项勘查工作.该专项勘查的主要任务是查明填埋场范围内垃圾的成分特征、空间分布...     

某简易垃圾填埋场封场工程设计要点

结合工程实例,分析总结了简易垃圾填埋场封场设计中的3个要点问题,即堆体整形、防渗和气体导排的解决方案,对国内同类型的垃圾填埋场封场工程具有一定的借鉴作用。     

污染物在填埋场底部非饱和土中的一维扩散解析解

为了揭示非饱和状态时污染物在填埋场底部土层中的运移规律,建立了污染物在非饱和土中的扩散模型。模型考虑了零浓度和零通量等下边界条件。在假设土层体积含水量随深度线性分布的基础上,利用分离变量法结合广义正交理论推导了该模型的解析解。解析解计算结果和有限元软件COMSOL Multiphysics 4.2的计算结果符合很好,并可退化到稳态解。100年时非饱和土底端污染物通量为91 g/ha/a,是孔隙度0.3时饱和土底端通量(63 g/ha/a)的1.4倍,是孔隙度0.6时通量(126 g/ha/a)的0.7倍。当土层上下端总体积含水量一定时,同一时刻土层底部污染物相对浓度随顶端含水量增大而减小;土层底部污染物通量变化则很小。本文解析解可用于复杂数值模型的检验,实验数据的拟合和填埋场防渗系统的初步设计等。     

某弃废非正规垃圾填埋场初步调查与分析

通过钻探、样品采集、样品检测等方式,对某废弃非正规垃圾填埋场堆体垃圾的体量、埋深、物理性质、填埋气质量浓度、渗滤液污染特性、基底原状土壤污染现状等进行了初步调查.调查结果显示,该垃圾填埋场堆体的面积约25000m2,堆填体积约200000 m3;混合垃圾的密实度不高,堆体会随垃圾的持续降解而出现不均匀沉降;垃圾湿基低位...     

河南省某垃圾填埋场地下水中邻苯二甲酸酯分布特征与成因

某垃圾填埋场地下水和地表水的分析测试结果表明:16个样品中,14种PAES的检测率为100%,其中DEHP的浓度最高,变化也较大,DOP的浓度较高,但是变化不明显,DEP的含量不高,浓度的变化几乎为常数。由于受水文地质条件和人工开采的影响,垃圾填埋场北侧ZK北孔的PAES的总浓度高于垃圾填埋场周围地下水和地表水中PAES的总浓度;PAEs含量和TSS、TDS、EC、pH以及芴、菲、蒽、荧蒽、芘之间没有线性关系,表明它们来源和迁移转化机理是不同的。目前垃圾场周围地下水和地表水中的PAES都没有超过国家饮用水质量标准,然而,为了防止进一步污染,必须对PAES的污染问题给予极大的关注。     

城市生活垃圾填埋场沉降分析与计算

城市生活垃圾填埋场无论在填埋过程中还是封顶后都会产生显著的沉降.填埋场的沉降一方面可以增加场区的垃圾消纳量,另一方面将对填埋场的维护和场地再利用产生不利影响.垃圾填埋体的沉降受垃圾土的自重压缩和有机质降解的综合影响.本文从分析填埋场沉降机理人手,提出填埋体的沉降由主沉降、次沉降和有机物分解沉降三部分组成,并给出了沉降估算公式;结合工程实例分析了填埋体的沉降过程,计算表明,一座设计容量为472万m3,设计填埋高度73m的填埋场的扩容率可达97%;封顶后的最终沉降约为填埋高度的10%.文中提出了实行分区填埋、分层压实和加速有机物分解等控制填埋场沉降的建议.     

简易垃圾填埋场污染控制与生态恢复

<正>我国简易垃圾填埋场历年垃圾堆存量达数十亿吨,其释放的污染物将对环境产生长期而巨大的影响。简易垃圾填埋场存在安全隐患由于缺乏系统的规划设计,简易垃圾填埋场在污染控制方面十分薄弱,虽然采取一些补救措施,但缺     

兰州某铝厂旧址周围土壤重金属污染及分布特征

研究了兰州某铝厂旧址周围土壤重金属形态特征,找出了该土壤中重金属元素的形态分布及变化规律,分析了引起7种重金属元素形态变化的主要因子。结果表明,该铝厂周围土壤重金属Cu、Mn、Ni、Pb、Zn、Cr、Cd污染严重。各重金属元素的含量随样品采集半径的增加而减少,7种重金属的形态分析结果表明,重金属污染主要以残渣态为主,Cd、Mn和Cr的弱酸态占有较大的比例,其中Cd的生态风险性最高。同时对重金属的环境效应和生态风险作出一定的评价,为治理和改善该地区土壤环境质量积累科学数据。     

矿区土壤重金属污染现状及对策

介绍了矿区土壤重金属污染的现状、污染特点、污染来源，同时提出了相应的治理对策，指出植物修复是一种有前途的土壤污染治理技术。     

有色金属矿区土壤重金属污染调查与修复研究进展

有色金属矿区是土壤重金属污染的主要地区之一,本文主要基于土壤重金属元素基准值、土壤理化特征、土壤重金属元素空间分布特征、土壤重金属元素形态特征、土壤重金属污染源同位素示踪等方面调查,为生物修复,物理、化学和联合修复的不同修复方法选择及土壤重金属污染监测提供科学依据。     

Long-term distribution, mobility and plant availability of compost-derived heavy metals in a landfill covering soil

The application of municipal waste compost (MWC) and other organic materials may serve to enhance soil fertility of earthen materials and mine spoils used in land reclamation activities, particularly in the recovery of degraded areas left by exhausted quarries, mines and landfill sites among others. The long-term distribution, mobility and phytoavailability of heavy metals in such anthropogenic soils were studied by collecting soil samples at different depths over a 10 y chronosequence subsequent to amendment of the top layer of a landfill covering soil with a single dose of mechanically-separated MWC. Amendment resulted in a significant enhancement of the metal loadings in the amended topsoils particularly for Cu, Zn and Pb, which were also the predominant metals in the compost utilised. Although metals were predominantly retained in the compost amended soil horizon, with time their vertical distribution resulted in a moderate enrichment of the underlying mineral horizons, not directly influenced by compost amendment. This enrichment generally resulted from the leaching of soluble organo-metal complexes and subsequent adsorption to mineral horizons. However, in the course of the 10-y experimental period, metal concentrations in the underlying horizons generally returned to background concentrations suggesting a potential loss of metals from the soil system. Analysis of the tissues of plants growing spontaneously on the landfill site suggests that metal phytoavailability was limited and generally species-dependent.     

Identification of organic compounds in leachate from a waste tip

Two different types of leachate from a municipal waste tip have been analyzed. The first type of leachate was collected from a waste tip in the acidification stage. The organic load of this leachate was high and consisted mainly of free volatile acids (over 95% of the TOC). Volatile amines and ethanol were also present (0.8 and 0.7% of the TOC respectively). The leachate was extracted with hexane and the extract was analyzed with infrared and nuclear magnetic resonance spectroscopy and a gas chromatograph-mass spectrometer combination. In the extract alcohols, hydrocarbons, esters, terpenes and phthalates have been identified. High molecular weight compounds were present only in a low concentration.The second type of leachate was collected from a waste tip in the methane fermentation stage. The organic load was relatively low. An important part of the organics was identified as high molecular weight compounds. About 32% of the organic carbon consisted of compounds with a molecular weight over 1000. Acids, amines and alcohols could not be detected. This means that the organic compounds present were end products of degradation processes.Furthermore there was a remarkable difference in heavy metal content between the two types of leachate.     

Migration and speciation of lead in a river system heavily polluted from a smelter

Anodic stripping voltammetry was used for the study of the migration and speciation of lead in surface waters affected by atmospheric deposits around a smelter, by ore mining and urban runoff. Three physiocochemical forms of lead were distinguished: dissolved-labile (Pb²⁺, PbOH⁺ and PbCO₃), dissolved-bound (colloids or strong complexes) and particulate (retained by 0.40 μm membrane filter). Labile forms represented a very significant part of lead input from the washout of the atmospheric deposits, whereas most of lead from urban runoff and ore mining was in particulate or bound forms. Rather large stability of high concentrations of the labile forms of lead in the waters was found. It has been concluded that the precipitation of sparingly soluble lead compounds is not a primary factor controlling the concentration of dissolved lead in stream waters. The migration and speciation of lead was strongly affected by water flow rate. With increasing water flow rate, the concentration of particulate and labile lead increased whereas the concentration of bound forms decreased. Most of the lead was carried downstream in a small river during high water flow rate, but sedimented in a larger river. Rapid removal of lead by sedimentation occurred during low streamflow conditions.     

Contamination assessment of heavy metals in the soils of an abandoned copper mine in Lasail,Northern Oman

ABSTRACT

Abandoned mine areas exhibit heavy metal contamination. This severely reduces the soil quality. This paper concerns the assessment of soils near an abandoned copper mine in Lasail, northern Oman. Seventy-two soil samples were collected and analysed for heavy metals using inductively coupled plasma optical emission spectrometry (ICP-OES). The extent of heavy metal pollution was evaluated based on the geo-accumulation index (Igeo), enrichment factor (EF), and pollution index (PI). According to these indices, Copper (Cu), Mercury (Hg), Zinc (Zn), Arsenic (As) and Iron (Fe) are impacting the soils. Of these, Cu and Hg concentrations are 50 and 300 times more than the permissible limits set by the World Health Organization (WHO). There is an urgent need for the remediation and restoration of the soils in this area and a proposal is presented here.     

黔南碳酸盐岩区水稻-根系土中硒、重金属的迁移与积累特征

为了查明黔南碳酸盐岩区水稻-根系中土硒、重金属的迁移与积累特征、水稻-土壤系统硒与重金属元素的相互关系,研究影响水稻对硒和重金属元素吸收的影响因素。本文通过对黔南独山—荔波一带稻作区水稻及对应根系土样品各项指标的采集分析,测试了水稻的Se、As、Cd、Cr、Pb、Hg含量与根系土的Se、As、Cd、Cr、Pb、Hg、SiO₂、Al₂O₃、Fe₂O₃、pH、SOM含量。结果表明根系土中Se、Cd、Cr、Pb、As呈伴生关系,稻米对Se和重金属的富集能力为：Cd>Se>Cr>As。其中根系土中Al₂O₃、Fe₂O₃、SOM与硒、重金属为正相关关系,稻米K_Se与根系土中Se、Cr、Hg、Pb、As、Al₂O₃、Fe₂O₃、SOM呈极显著负相关关系,稻米中Se、Cd富集系数...     

Migration of elemental mercury through soil from simulated burial sites

The potential migration of metallic mercury from shallow land burial sites into groundwater has been investigated by means of laboratory column tests and radioactive tracers. It was found that mercury will dissolve in water on concentrations of 20–80 ppb and high concentrations of EDTA in water will increase mercury solubility by complex formation. Standing mercury was found to penetrate up to 3–4 cm into dry soil columns under its own head. Flow tests with soil-equilibrated water, EDTA solutions or kaolin suspensions all showed little demonstrable migration or entrainment beyond the top 2 cm of the columns.     

Heavy metals in the surficial sediments of Fontana Lake, North Carolina

Concern about the possible contamination by heavy metals of Fontana Lake (reservoir) and potential sources of such materials led to a study of surficial sediments. Samples of sediment were collected in the main body of the lake and near the mouths of its major tributaries and analayzed for magnesium, iron, aluminum, manganese, zinc, copper and mercury. Although the drainage area of the reservoir is primarily forested and rural without major industrial developments, the results indicated that manganese, copper and zinc were present in concentrations similar to areas receiving industrial pollution. Chemical analyses of pyritic materials in the watershed (e.g. schists or Anakeesta formation) showed relatively high concentrations of many of the same metals present in Fontana sediments. It appears, therefore, that the metals in the lake sediments represent materials derived from geological sources, although airborne contributions of certain metals cannot be ruled out.