二维电极电解法去除水中硝酸盐试验研究

目前硝酸盐污染已经严重影响了地下水水质,对饮用水安全构成了一定威胁。本研究拟采用电化学方法去除水体中硝酸盐,探究其机理、动力学、影响因素及实际地下水处理方法,为地下水脱氮提供参考。研究结果表明:在无氯离子体系下,30.0 mg/L的硝酸盐在2.0 A电流下电解,其一级反应动力学常数为0.040 h-1,产物中54%为氨氮,46%为氮气。在添加300.0 mg/L氯离子条件下电解,一级反应动力学常数为0.029 h-1,其产物主要为氮气。硝酸盐去除速率随着硝酸盐初始浓度和电流增加而增加,随着氯离子浓度增加而略微减少。对实际地下水水样的电解结果表明,20.0 mg/L的硝酸盐在2.0 A、100.0 mg/L氯离子条件下电解,其一级反应动力学常数为0.031 h-1,产物主要为氮气。二维电极电解过程中,硝酸盐扩散至阴极表面速率较慢,电解效率较低。     

内蒙古河套灌区解放闸灌域地下水水质与硝态氮时空变化研究

为了研究节水工程改造及节水灌溉对区域农田地下水及硝态氮淋失污染的影响,以内蒙古河套灌区解放闸灌域为研究区域,对整个作物生长期的3月、5月、7月、9月分别取水样进行水化学和硝态氮测试分析。对2003年与2008年区域内27眼井地下水硝态氮的时空分布特征进行研究,结果表明:在2003年间,夏灌前解放闸灌域地下水硝态氮质量浓度大于10 mg/L的面积占灌域总面积的9.95%,全年平均硝态氮质量浓度大于10 mg/L的面积占灌域总面积的9.02%;2008年3月硝态氮质量浓度大于10 mg/L的面积占灌域总面积的5.22%,全年平均硝态氮质量浓度大于10 mg/L的面积占灌域总面积的5.20%。2003年与2008年的监测结果及时空分布趋势说明该地区地下水存在较严重的面源氮污染,但节水灌溉的实施可能对减少河套灌区的化肥淋失和地下水污染具有积极的改善作用,特别是由于秋浇水量的减少,地下水位下降,对减少地下水硝态氮污染具有明显的作用。     

高盐度底泥水库工程布置及运行对供水安全的影响

为保障高盐度底泥水库供水氯离子质量浓度达标(小于250 mg/L),在水库闸门工程布置及水库正常运行期间对高盐度底泥这一氯离子释放源对水库水质的影响进行研究。以天津市北塘水库为例,针对水库闸门布置方案比选及水库在运行期间的水质咸化问题,考虑高盐度底泥氯离子释放,建立三维水动力水质模型进行数值模拟。结果表明:引水、供水闸门的空间布置直接影响供水水质,引水闸位于西南角同时开启3个供水闸的方案为较优方案,该方案下基本无死水区域,供水水质在供水8 d后达标;在水库静置期,底泥氯离子释放速率与底泥含盐量呈正相关,在最不利情况下,水库氯离子在底泥释放55 d后浓度超标。     

穆兴平原北区浅层地下水水化学分布特征 及其形成机理

采用2016年8月采集的192个地下水样品水化学数据,查明了穆棱河—兴凯湖平原(穆兴平原)北区第四系浅层地下水溶解性总固体(TDS)和地下水化学类型分布特征,并结合研究区水文地质条件和人类活动影响分析其形成原因。结果表明:穆兴平原北区浅层地下水主要以TDS小于0.5g/L的淡水为主,未见TDS大于1.0g/L的微咸水。地下水TDS受含水介质、溶滤作用和地表水-地下水交互作用影响,在区内呈多种分带规律。区内浅层地下水化学类型不具备明显的水平分带规律,主要以HCO_3-Ca·Mg型水为主,与人为活动较少的20世纪60年代背景水化学类型(HCO_3-Ca·Na型水)对照,地下水中硫酸根、氯离子及镁离子的增加与煤矿开采、生活用水污染及大范围农业施肥等人类活动相关。     

北京市朝阳区地下水化学特征及其变化规律

为了揭示北京市朝阳区水化学特征的形成机制,采集2007—2009年不同季节中共计144个地下水样品进行监测,应用相关分析法、水化学方法和离子比例法分析地下水水化学特征、影响因素和变化规律。结果表明:丰水期和枯水期地下水水化学组分差别较小。地下水阴离子中HCO3-占绝对主导地位且含量相对稳定,质量浓度均值在290～302 mg/L,而Cl-受环境影响质量浓度变化较大,变异系数在95.7%～132%,阳离子则以Na+、Ca2+为主,质量浓度均值分别为53～72 mg/L和49～62 mg/L,且Na+质量浓度变化稍大。总体上朝阳区地下水TDS中等,均值为449.4 mg/L,与Cl-、SO24-、HCO3-、Ca2+和Mg2+的质量浓度呈显著正相关关系。地下水化学类型以HCO3-NaCa为主,少数地段出现HCO3Cl-CaMg和HCO3SO4-NaCa。     

山东省莒县沭河盆地地下水资源评价

通过物探、钻探手段对沭河盆地的水文地质结构、补径排条件进行研究,建立水文地质模型,并利用GMS数值模拟和内梅罗综合指数法对地下水开采潜力及水质进行评价。结果表明:沭河盆地含水层分布具各向异性,按含水层厚度可划分为两个富水区;地下水补给来源以大气降水和河流侧渗补给为主,排泄途径主要为人工开采,地下水正均衡2 312.85万m3/a;经模拟不同开采情况下地下水变化情况,确定莒县沭河盆地地下水开采潜力为6.1万m3/d;地下水水质达到Ⅲ级及以上标准的区域占总面积的71.4%,基本满足供水质量要求。     

沧州市地下水开采-地面沉降数值模拟

以沧州市地下水开采引起的地面沉降为例,在分析研究区地质和水文地质条件的基础上,得到研究区地下水开采与地面沉降地质概化模型,建立地下水三维渗流和土体垂向一维变形耦合数值模型,在完成模型识别验证的基础上,预测了现状开采条件下从2010年末到2025年末地下水流场的变化特征和地面沉降的变化趋势。结果表明,到2025年底,整个沧州市范围内累计地面沉降量最大值为475 mm,最小值为270 mm。     

氯离子浓度和碱度对给水管网管垢重金属锰释放的影响

通过静态释放实验,研究了水源切换造成原水中不同浓度的氯离子和碱度对管网管垢中重金属锰释放的影响。选取郑州市给水管网管段,设计模拟释放反应装置,配制不同浓度氯离子(5 mg/L、23.1 mg/L、60 mg/L、90mg/L)和碱度(52.5mg/L、125mg/L、200mg/L)的实验用水,比较分析氯离子浓度和碱度变化对管垢重金属锰释放的影响。根据实验结果初步推断:氯离子浓度和碱度与管垢中金属锰的释放浓度有较高相关性,且实验中氯离子浓度是影响管网管垢锰释放的首要因素。当氯离子浓度为30 mg/L,停留时间60h,锰的释放量达到最大为108mg/L,之后释放浓度趋于平稳。在氯离子浓度促进锰释放的条件下,碱度与管垢中锰的释放量表现出明显相关性。实验结果可为水源切换引起的水质差异对给水管网管垢锰释放问题提供一定参考。     

盐城市地下水资源调查评价

在查明盐城市地下水各含水岩组的水文地质特征、开采现状和水位动态的基础上 ,运用数值法对盐城市地下水资源进行评价 ;核定了全市市、县 (市 )、乡 (镇 )三级行政区域地下水可开采量 ,其中Ⅱ ,Ⅲ ,Ⅳ承压含水层可开采量分别为 4992万m3 /a ,6 10 3万m3 /a ,5 478万m3 /a .最后制定了全市地下水合理开发利用规划 ,调减开采区面积 16 33km2 ,控制开采区面积 2 34 8km2 ,扩大开采区面积110 83km2 .     

文安县高氟地下水的分布特征及关键水化学性质分析

为进一步认清河北省文安县高氟地下水的水化学性质,在水文地质调查以及取样分析的基础上,采用水化学特征分析、多元统计分析和水化学成因分析等手段阐明文安县高氟地下水的分布特征和关键水化学性质.结果表明：文安县深层地下水氟化物含量0.56～4.19 mg/L,总体分布是中北部偏高;其关键水化学特征是pH值7.7～8.7、总碱度高于211 mg/L、总硬度低于90 mg/L,水化学类型为典型的Na-HCO3型;在文安县地下水环境条件下,总碱度、碳酸氢根以及钠离子是促进高氟地下水形成的关键水化学因素;当2.0 mg/L＜F-＜ 3.5 mg/L时,地下水中Ca2＋与F-有拮抗作用.通过氯碱指数和饱和指数分析可知,研究区域高氟地下水的形成主要是水-岩间的阳离子交换反应和氟矿物的溶解-沉淀反应.     

Observations on Vertical Variability in Groundwater Quality: Implications for Aquifer Management

This work demonstrates significant vertical variability in the chemical composition of groundwater (Cl⁻ from 150 to 550 mg/L, NO₃^-{\rm{NO}}_{3}^{-} from 3 to 70 mg/L, trichloroethene from 350 to 55,000 μg/L and Cr_Total from 3 to 2,900 μg/L) along a 130 m thick vertical section passing through two subaquifers of the Costal Plain aquifer of Israel. Water samples were obtained by multilevel sampler under natural gradient flow conditions from a monitoring well which penetrates the entire aquifer. The vertical chemical variability detected at a single point in time in this well was found to be similar to the range of concentrations detected for Cl⁻ in pumping wells located over an area of about 1,000 km² in the same aquifer. Similarly, vertical variations in NO₃^-{\rm{NO}}_{3}^{-} concentration in the single monitoring well represent more than 50% of the total variation in nitrate levels in pumping wells sampled across the entire aquifer. These results graphically illustrate that data from pumping wells, which extract unknown mixtures of groundwater from different depths, cannot provide adequate information about groundwater quality for management purposes.     

浅层地下水水化学特征与土体盐分相关性研究

为研究南通地区浅层地下水与土体盐分特征的相关性,采集了31件水样、220件土样,并收集了60组水质资料,分析了浅层地下水水化学特征和土体盐分特征。研究表明:浅层地下水自西向东,TDS逐渐增大,主要为咸水和盐水,水化学类型为Cl—Na型,TDS与各离子(K⁺、Na⁺、Ca²⁺、Mg²⁺、Cl^-、SO₄^2-)的相关性高;土体盐分特征和地下水基本相似,自西向东逐渐增大,随着深度的加深也逐渐增大,盐渍土类型为氯盐渍土,以弱盐渍土为主,表明土体中的盐分主要来自于地下水;地下水的TDS和土体的总盐量、K⁺、Na⁺、Mg²⁺、Cl^-、SO₄^2-的相关性都很高,为此建立多个关于TDS与土体盐分特征的线性预测模型,平均相关系数达0.839,平均预测准确率达到了88.93%,效果良好,从而可在不钻探成井的条件下,依靠采取的土样判断地下水的TDS,节省了钻探成井的费用。     

Characterization of a Regional Aquifer System in the Maritimes Basin,Eastern Canada

A regional hydrogeological study was carried out in the Maritimes provinces, in one of the main aquifer systems in Canada. The study area covers a land surface of 10,500 km², of which 9,400 km² is over Carboniferous and younger rocks. The sedimentary fractured bedrock is composed of a sequence of discontinuous strata of highly variable hydraulic properties, and is overlain by a thin layer of glacial till (mostly 4 to 8 m). Depending on areas, 46 to 100% of the population relies on groundwater for water supply. Almost all residential wells are shallow (28 m on average) open holes that are cased only through the surficial sediments. This paper describes a regional hydrogeological investigation based on targeted fieldwork, the integration of a wide variety of existing multisource datasets and groundwater flow numerical modelling. The aim of this paper is to present the current state of understanding of the aquifer system in a representative area of the Maritimes Basin, along with the methodology used to characterize and analyze its distinct behaviour at the regional, local and point scales. This regional hydrogeological system contains confined and unconfined zones, and its aquifer lenticular strata extend only a few kilometers. Preferential groundwater recharge occurs where sandy tills are present. The estimated mean annual recharge rate to the bedrock aquifers ranges between 130 and 165 mm/year. Several geological formations of this Basin provide good aquifers, with hydraulic conductivity in the range of 5 × 10⁻⁶ to 10⁻⁴ m/s. Based on numerical flow modelling, faults were interpreted to play a key role in the regional flow. Pumping test results revealed that the aquifers can locally be very heterogeneous and anisotropic, but behave similarly to porous media. Work performed at the local scale indicated that most water-producing fractures generally have a sub-horizontal dip along a north-east (45°) strike.     

江苏南通部分地区深层地下水咸化成因及对策

为了解江苏南通部分地区深层地下水水质咸化的状况及产生原因,对全市深层地下水的3个开采阶段进行了初步分析。找出了导致该地区深层地下水咸化的原因为：多年高强度开采、隔水层薄弱地区的越流补给、不规范的成井工艺等改变了深层地下水的正常流动与补给。根据研究结果,提出了加强开采管理、根据水文地质条件科学布井、强化取水许可全过程监管、全面回填报废管井等综合应对措施。     

Nitrate Accumulation and Other Components of the Groundwater in Relation to Cropping System in an Aquifer in Southwestern Spain

Inappropriate farming techniques and 4 years of drought (1992–1995) produced conditions for high nitrate concentration in an aquifer located in the Province of Seville (Southwest Spain). The objectives of this study were to study groundwater components and to determine the relationship between the cropping system and nitrate concentrations in groundwater. From October 1994 to May 1996, 16 groundwater samples were obtained from a network of 35 sample points. Groundwater concentrations were analysed by multivariate statistical techniques (factor and cluster analysis). Two factors were found: firstly, agricultural pollution and secondly, salinization (from natural mineralization of groundwater and from anthropogenic effects). High levels of NO_3– were closely associated with intensive cotton (Gossypium herbaceum L.) and potato production (Solanum tuberosum L.). The salinization factor includes electrical conductivity, Cl_–, Na₊, Ca_{2 +}, Mg_{2 +}, SO_{42 –} and HCO_3–. Our study permits the impact of crops on groundwater to be determined. In comparison to the other crops, cotton (Gossypium herbaceum L.) and potato (Solanum tuberosum L.) made the greatest contribution to nitrate pollution and salinization. Use of the groundwater for human consumption in drought periods could represent a public health risk. Alternative farming techniques for these crops such as monitored fractional fertilization and controlled irrigation are recommended.     

Numerical Simulation of Submarine Groundwater Flow in the Coastal Aquifer at the Palmahim Area, the Mediterranean Coast of Israel

The lower sub-aquifers of the Mediterranean coastal aquifer of Israel, at the Palmahim area, are hypothesized to be laterally blocked to connection with the sea, and thus to seawater intrusion. This is mostly due to the detection of fresh water bodies at these sub-aquifers. This study examine this hypothesis by using two dimensional numerical model simulations of the groundwater flow system at this area, which conducted in order to reveal which hydrogeological setting enables the existence of these fresh water bodies in the lower sub-aquifers and to assess the on-land pumping rates that will prevent their salinization. The hydrogeological settings were examined by steady state simulations followed by simulations of the last 15,000 years sea level changes. These simulations imply that the presence of fresh water in the lower sub-aquifer, whether blocked or connected to the sea, requires offshore separation between the upper and lower sub-aquifers. On-land pumping simulations, with a well located inside the lower sub-aquifers at the shoreline, show a maximum pumping rate of 250 m³/m strip width/year, hereafter m²/year, to prevent the salinization of the lower sub-aquifers. The various pumping scenarios revealed differences in salinization trends between the scenarios with impermeable separating layers and those with semi permeable layers. Scenarios with extreme pumping rates emphasize these differences, and together with field test, can allow assessing the amount of separation between the sub-aquifers.     

江阴南部地区地下水禁采效应分析

简要介绍了江阴南部地区地质、水文地质条件、地下水开发利用及封井情况,阐述了区内地下水水位动态及地面沉降速率的变化趋势,对地下水禁采所产生的水位及环境效应进行了分析与总结。初步认为:江阴南部地区地下水开采量主要来自含水层的重力释水,地面沉降量主要为含水砂层的压缩变形量,地面沉降与地下水开采间的关系尤为密切,表现为地下水禁采后随着水位的缓慢回升,地面沉降速率迅速减缓。     

厄立特里亚Zara地区Koka金矿开采的地下水资源可持续性分析

在非洲干旱性气候条件下,水资源的补给量稀缺,做到地下水资源的有效平衡极其重要。在分析Zara科卡金矿水文地质条件的基础上,建立了准三维有限差分地下水流模型,模拟预测了科卡金矿开采期间和封场后,在丰水、枯水和平水3种气候条件下矿山供水对地下水水位降深的影响,并对有、无矿山供水条件下的地下水水位降深进行了对比分析。模拟结果表明:前1~3 a,日供水量约0.97×10~4m~3/a,在4~7 a,日供水量约在1.01×10~4m~3/a,矿山供水开采不会引起当地地下水资源枯竭,且矿山关闭后,含水层水位会很快恢复;即使在增加矿山供水和枯水气候同时出现的最不利条件下,井场中心出现最大地下水位降深为1.0~1.2 m,且距离井场中心距离约2km的边缘区域,地下水位降深仅为0.2 m。模拟结果可为高温干旱地区矿山的供水开采提供科学依据。     

应用非参数的MK和ITA方法分析地下水水质参数变化特征——以新三矿含水层为例

矿区地下水水质变化是影响矿区生态环境和矿井安全生产的制约因素之一,正确认识水质变化趋势是首要任务。根据以往实测水质参数pH、COD、Na~++K~+、Ca~(2+)、Mg~(2+)、Cl~-、SO_4~(2-)和HCO_3~-的数据,采用Mann-Kendall检验法(MK)和Innovative Trend Analysis(ITA)探讨新三矿由上而下6个不同含水层水质参数随时间的演变规律,并且针对不同的数值变化范围选用不同的ITA指数。通过比较,两种方法结果有很好的一致性,结论认为:相比MK检测法,定量的ITA法拥有更多的优点,可以图形化地表示分析结果,可以通过将水质参数值分为低、中、高水平更好地分析水质参数的趋势和次要趋势;8种水质参数中,Ca~(2+)和Mg~(2+)相较其他离子能表现出更显著的变化趋势;6种含水层中,大青灰岩含水层中Cl~-浓度的低、中值下降而高值上升,煤层顶板山西组砂岩含水层和底板奥陶系灰岩含水层大部分水质参数显著下降,矿化度逐渐降低。     

榆神矿区煤炭开采对水资源影响分区评价

利用渗流基本原理,推导得出榆神矿区煤炭开采对水资源的影响系数计算公式,提出影响程度分区方法及标准。通过对区内钻孔资料统计分析,计算得到528个影响系数,结合水文地质条件,将榆神矿区煤炭开采对水资源影响程度划分为无水采煤区、间接影响区、直接影响区3大类,并进一步划分成数个亚区,其面积分别为836、3 668、761 km~2,占矿区总面积的15. 88%、69. 67%、14. 45%。对比研究区及周边矿井涌水量实测数据,涌水量较大井田位置与本次分区结果一致,分区方法及标准正确可行,对水文地质条件相似区域具有借鉴意义。最后,根据典型煤矿排水特征及对水资源的影响,提出煤炭开采的水资源保护建议。