越流含水层系统地下水有毒元素污染数值模拟——以太原盆地地下水汞污染为例

提出了一个越流含水层系统考虑弱透水层吸附作用的地下水污染数学模型,模型应用于太原地地下水中汞污染的数值模拟,水位拟合误差为０．４０７－０．５０ｍ,汞离子浓度拟事误差小于４％－５％,表明模型可靠,合理,为定量预测越流含水层系统地下水污染提供了科学手段。     

AUTOMATED METHODS FOR ESTIMATING BASEFLOW AND GROUND WATER RECHARGE FROM STREAMFLOW RECORDS1

ABSTRACT: To quantify and model the natural ground water recharge process, six sites located in the midwest and eastern United States where previous water balance observations had been made were compared to computerized techniques to estimate: (1) base flow and (2) ground water recharge. Results from an existing automated digital filter technique for separating baseflow from daily streamflow records were compared to baseflow estimates made in the six water balance studies. Previous validation of automated baseflow separation techniques consisted only of comparisons with manual techniques. In this study, the automated digital filter technique was found to compare well with measured field estimates yielding a monthly coefficient of determination of 0.86. The recharge algorithm developed in this study is an automated derivation of the Rorabaugh hydrograph recession curve displacement method that utilizes daily streamflow. Comparison of annual recharge from field water balance measurements to those computed with the automated recession curve displacement method had coefficients of determination of 0.76 and predictive efficiencies of 71 percent. Monthly estimates showed more variation and are not advocated for use with this method. These techniques appear to be fast, reproducible methods for estimating baseflow and annual recharge and should be useful in regional modeling efforts and as a quick check on mass balance techniques for shallow water table aquifers.     

人工地下水回灌过程中溶解性有机物的去除及变化

在实验室通过模拟土壤柱研究了人工地下水回灌过程中溶解性有机物的去除及其三卤甲烷生成势和三卤甲烷生成活性的变化.利用XAD树脂将回灌水中的溶解性有机物分为3个部分：疏水性有机酸、过渡亲水性有机酸和亲水性有机物.疏水性有机酸的三卤甲烷生成活性高于过渡亲水性有机酸和亲水性有机物.土壤含水层处理（SAT）对亲水性有机物的去除率为68.51%,对疏水性有机酸和过渡亲水性有机酸的去除率分别为58.64%和41.86%.经SAT系统处理后,溶解性有机物及各有机组分的三卤甲烷生成势减少,而三卤甲烷生成活性升高.疏水性有机酸是生成三卤甲烷的主要有机组分.亲水性有机物在SAT系统进水中的三卤甲烷生成活性较低,但由于含量高,三卤甲烷生成势也较大.而过渡亲水性有机酸由于含量和三卤甲烷生成活性较低,三卤甲烷生成势也较低.     

3H和99Tc在黄土中的迁移特性比较

³H和⁹⁹Tc是低中放废物处置中2个重要的核素,在处置场的安全评价中十分重要.由于介质对³H和⁹⁹Tc的吸附较弱,常忽略其滞留性,并用³H标定地下水的流速.野外实验表明:在包气带中,黄土对⁹⁹Tc的吸附大于³H;在含水层中,黄土对³H迁移的影响大于⁹⁹Tc.本文根据实验数据,采用非平衡吸附模式NESOR程序分别模拟了³H和⁹⁹Tc在黄土包气带和含水层中的迁移过程.模拟结果表明:⁹⁹Tc在黄土包气带中的分配系数范围为0.05～0.055mL/g;³H在黄土含水层中分配系数为0.116mL/g,该参数是黄土对³H和⁹⁹Tc综合影响的结果,其滞留机理尚待研究.     

DEEP WELL DISPOSAL OF SECONDARY EFFLUENT IN DADE COUNTY,FLORIDA1

ABSTRACT: Data were obtained from drilling and testing of a test injection well for deep underground injection of waste water effluent from the proposed 50-million-gallon-per-day (mgd) South District Regional Wastewater Treatment Plant of the Miami-Dade Water and Sewer Authority, Dade County, Florida. The drilling operation progressed in stages, each stage coverting the strata to be sealed off by the 48-inch, 40-inch, 30-inch, and 20-inch casings, respectively. Total depth of the well is 3,200 feet. The top of the saline, cavernous, dolomitic Boulder Zone was found at 2,790 feet below the surface and is separated from the Floridan aquifer above by approximately 1,100 feet of confining limestone layers. These confining layers were determined, by packer testing, to be very effective. The transmissivity of the Boulder Zone was estimated to be 14 × 10⁶ gallons per day per foot (gpd/ft) from the data obtained from pump out tests. An 8,000-gallon-per-minute (gpm) injection test was conducted to confirm well performance under operating conditions. Based on all of the data obtained, it was concluded that underground injection into the Boulder Zone of secondary waste water effluent from the proposed treatment plant is feasible, both hydraulically and environmentally. A monitoring system was proposed to provide a record of the effects of injection on the subsurface environment.     

矿山开发对地下水的影响研究

矿山开采中的环境地质问题目前引起了足够重视,含水层破坏问题就是其中之一,将会影响到地下水资源.文章以个旧矿区为例,探讨了矿山开采引起的含水层结构破坏、地下水水位变化、地下水补径排条件改变和水质污染等现象,对矿山地下水综合利用及矿山地质环境保护提出参考建议,为矿山环境恢复治理提供科学依据.     

纳米乳化油修复地下水硝酸盐过程中产气及微生物增殖代谢对多孔介质堵塞的模拟评估

为有效评估纳米乳化油原位处理地下水硝酸盐过程中,产气及微生物增殖代谢对含水层多孔介质的堵塞作用,以纳米乳化油为碳源,采用市售反硝化菌剂接种微生物进行硝酸盐降解批实验研究,探讨产气及微生物增殖代谢的动态变化及特征,并基于Kozeny-Carman(K-C)方程、Clement、Pham及Kozeny Grain(KG)模型,对假定含水层一维流模拟柱,预估产气及微生物增殖代谢造成的渗透性损失,识别堵塞过程及主导因素.结果显示,反硝化菌降解效果良好,硝氮总去除率达90.23%.CO_2及N_2为主要产气成分,降解1 mg硝氮对应的平均CO_2产气量为0.71 mL,平均N_2产气量为0.14 mL;微生物代谢产物胞外聚合物以蛋白质及多糖为主,降解1 mg硝氮平均蛋白产量为0.64 mg,平均多糖产量为0.16 mg.在含水层不与外界交换气体的假设前提下,K-C方程预测显示产气可在2个周期内造成渗透性完全损失,Clement、Pham及KG模型评估的微生物增殖代谢造成中、细砂渗透性损失分别为10.87%～31.10%、12.77%～48.32%,分析认为初期细胞生物量是导致渗透性骤降的关键因素,后期为细胞生物量和胞外聚合物共同作用.此外,封闭体系中产气是堵塞的主导因素,随着含水层开启程度增加,产气的贡献占比会下降,微生物的贡献占比提高.因此,对于相对封闭的含水层系统,探索增强其开放状况是缓解堵塞的有效途径之一.     

孔隙裂隙含水层生物降解的模型参数试验

着重试验了生物降解数学模型的模式参数的变化对生物降解的影响。并根据数值实验结果对模式的参数相互作用大小进行了分类。     

华北城市地区潜水中主要离子含量变化的反应途径模拟

近三十年来，由于污染，华北城市地区潜水中主要离子如ＣＡ＾２＋、Ｍｇ＾２＋等含量逐年升高，影响工农业生产，本采用反应途径模拟的方法对上述情况进行了研究，作共设计了７种反应途径，分别模拟了含碳酸盐或硅酸盐、铝硅酸盐较丰富地区地下水中盐效应和ＣＯ２分压升高对基主要离子含量的影响，模拟过程中考虑了２２种化学反应，３３种存在形式（包括气体、固体）。结果表明，盐效应和ＣＯ２分压升高对地下水中Ｃａ＾２＋、Ｍ     

Deep Geological CO2 Storage: Principles Reviewed, and Prospecting for Bio-energy Disposal Sites

The principles of hydrocarbon exploration and production provide well-established and tested principles and technologies to investigate storage of fluids in the subsurface. CO₂ can be stored in the subsurface using settings of: (A) thick permeable coal seams; (B) depleted oil and gas fields; (C) saline aquifers of regional extent, with an overlying seal. The North Sea Sleipner project shows that CO₂ can be injected into the pore space of deep geological aquifers deeper than 800 m at 1 Mt/yr, using established technology. Suitable sediment sequences of saline aquifers exist in all hydrocarbon-producing areas, are volumetrically much larger than exploited oil and gas fields, and hold the potential to easily store all worldwide CO₂ emissions until 2050. Geological principles are established to assess entire continents for candidate sites of CO₂ storage. This shows that opportunity may be widespread, but needs more specific local investigations. Onshore sub-Saharan Africa is considered the most problematic region – but even here there are potentially viable sediment sequences. No demonstration projects currently exist for CO₂ capture and storage using small-scale onshore facilities. A simple estimate, assuming CO₂ value of $20 per ton, suggests that single boreholes onshore may be viable over 20 years with supply rates of 100,000 ton CO₂ per year. In principle, atmospheric CO₂ could be captured by cultivated biomass, and co-fired in existing power stations. Or energy crops could be grown, CO₂ to be used, and stored deep below ground, in a country distant from an original fossil-fuel CO₂ emission site.