UTILIZING INDUCED RECHARGE FOR REGIONAL AQUIFER MANAGEMENT1

ABSTRACT: The deep aquifers of the Portland Basin are used as a regional water supply by at least six municipalities in Oregon and Washington. Maximum continuous use of the aquifers in 1998 was 13 mgd and peak emergency use was 55 mgd. Continuous use of the deep aquifers at a rate of 55 mgd has been proposed and inchoate water rights have been reserved for expansion of pumping to 121 mgd. A study was completed, using a calibrated ground water flow model, to evaluate the role of induced recharge from the Columbia River in mitigating aquifer drawdown from continuous‐use and expanded pumping scenarios in the center and eastern areas of the basin. The absolute average residual was less than 3.6 feet for steady‐state model calibrations, and less than 8.0 feet for transient calibration to a 42 mgd pumping event in 1987 with 170 feet of drawdown. Continuous use of the aquifers at a rate of 55 mgd is predicted to increase drawdown to 210 feet. Expansion of pumping to 121 mgd in the center basin is predicted to cause 400 feet of drawdown. However, expansion of pumping in the east basin is predicted to result in only 220 feet of drawdown because of induced recharge from the Columbia River.     

胶态微泡沫用于冲洗含水层的迁移分布特征

目前有关胶态微泡沫（CGAs）冲洗含水层过程中的迁移分布特性尚不明确,本研究利用二维模拟实验详细探究了注入速率、表面活性剂浓度和介质条件对CGAs迁移分布时空变化特征的影响.结果表明,在单侧单点注入条件下,CGAs的波及区域形状近似半圆形,迁移锋面相对规则;CGAs破裂产生的泡沫液分布在其迁移锋面四周,泡沫气体受地下水浮力影响向上方迁移,导致出现在纵向向上迁移距离大于向下迁移距离的"向上漂移"现象.表面活性剂浓度对CGAs的迁移分布影响较小;注入流速低或介质渗透性差,CGAs均会在迁移后期出现明显的“向上漂移”现象,同时其波及区域形状逐渐趋向于半椭圆形;恒定流量注入CGAs,其在含水层中的波及面积存在最大值.相对传统液相冲洗液,CGAs在非均质含水层中迁移分布较为均匀,受介质非均质性影响较小.     

Silica-quaternary ammonium “Fixed-Quat” nanofilm coated fiberglass mesh for water disinfection and harmful algal blooms control

Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of receiving surface waters. Formation of unwanted disinfection by-products(DBPs) resulting from conventional disinfection technologies reveals the need for the development of new sustainable alternatives. Quaternary Ammonium Compounds(QACs) are cationic surfactants widely known for their effective biocidal properties at the ppm level. In this study, a novel silica-based antimicrobial nanofilm was developed using a composite of silica-modified QAC(Fixed-Quat) and applied to a fiberglass mesh as an active surface via sol–gel technique. The synthesized Fixed-Quat nanocoating was found to be effective against E. coli with an inactivation rate of 1.3 × 10~(-3) log reduction/cm min. The Fixed-Quat coated fiberglass mesh also demonstrated successful control of Microcystis aeruginosa with more than 99% inactivation after 10 hr of exposure.The developed antimicrobial mesh was also evaluated with wild-type microalgal species collected in a water body experiencing HABs, obtaining a 97% removal efficiency. Overall,the silica-functionalized Fixed-Quat nanocoating showed promising antimicrobial properties for water disinfection and HABs control, while decreasing concerns related to DBPs formation and the possible release of toxic nanomaterials into the environment.     

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.     

Scenario simulations of CO2 injection feasibility, plume migration and storage in a saline aquifer, Scania, Sweden

Deep saline aquifers have large capacity for geological CO₂ storage, but are generally not as well characterized as petroleum reservoirs. We here aim at quantifying effects of uncertain hydraulic parameters and uncertain stratigraphy on CO₂ injectivity and migration, and provide a first feasibility study of pilot-scale CO₂ injection into a multilayered saline aquifer system in southwest Scania, Sweden. Four main scenarios are developed, corresponding to different possible interpretations of available site data. Simulation results show that, on the one hand, stratigraphic uncertainty (presence/absence of a thin mudstone/claystone layer above the target storage formation) leads to large differences in predicted CO₂ storage in the target formation at the end of the test (ranging between 11% and 98% of injected CO₂ remaining), whereas other parameter uncertainty (in formation and cap rock permeabilities) has small impact. On the other hand, the latter has large impact on predicted injectivity, on which stratigraphic uncertainty has small impact. Salt precipitation at the border of the target storage formation affects CO₂ injectivity for all considered scenarios and injection rates. At low injection rates, salt is deposited also within the formation, considerably reducing its availability for CO₂ storage.     

离柳矿区石炭系薄层灰岩渗透系数空间分布研究

基于矿井涌水量计算及水资源评价需要,首先运用注水试验代替抽水试验,求取了太原组灰岩含水层的渗透系数.根据后期同一含水层井下放水试验资料,利用VISUAL MODFLOW建立了水文地质三维非稳定流数值模型,通过分区拟合调参,获得了含水层各分区的渗透系数.通过对渗透系数及其空间分布规律的对比研究,发现渗透系数随含水层埋深增大而逐渐减小.注水试验比放水试验所得渗透系数值小,前者是后者的35.6％-50.8％.     

WATER USE CONFLICT NEAR MADISON,NEBRASKA1

ABSTRACT: Nebraska statutes give first preference for use of ground water to domestic purposes, second to agriculture, and third to manufacturing or industrial purposes. Rapid growth in the number of irrigation wells has caused an increasing number of water use conflicts. One such conflict arose from the installation and use of an irrigation well near Madison in Madison County, Nebraska. Pumping from the irrigation well coincided with head declines in nearby domestic wells screened in the same sand and gravel, but appeared unrelated to water level changes in wells screened in a higher saturated sand. A drawdown-recovery test was performed to determine the degree of hydraulic connection between the wells involved. Operation of the irrigation well was determined to be the cause of the head decline in nearby domestic wells screened in the same sand and gravel. Partly as a result of this conflict, legislation recently introduced into the state legislature would require that wells of higher preference be “reasonably” constructed if wells of lower preference are to be held liable for head loss.     

曹妃甸地区地下水水化学特征及影响因素的R型因子分析

通过对2008年12月份在曹妃甸地区采集测试的25组水化学资料进行分析,探讨了该区地下水的水化学特征,并利用R型因子分析法对影响该区地下水化学组分的4个主要因素进行了研究,结果表明:区内浅层地下水基本都为高矿化的Cl-Na型,深层地下水水化学类型具有一定的水平分带性;高矿化的地表水和潜水主要是蒸发浓缩作用和沿海土壤易溶盐含量高共同影响的结果,深层地下水水化学组分主要受含水介质中易溶盐分组成和补给水高碳酸含量的影响;地下水中NH4+、NO3-和NO2-的广泛检出反映了农业生产和人们生活排污等人类活动对地下水化学组分的影响。     

海口市地下水含水层结构三维可视化建模初探

本文在对海口市水文地质条件及钻孔资料分析的基础上,对各钻孔柱状图进行了研究,重新统一了岩性和含水层划分的标准,绘制了反映各含水层空间结构的等值线图,并结合研究区的边界条件、地表地形参数等,在GMS软件平台上实现了海口市地下水系统结构的三维可视化,形象直观地再现了含水系统的空间结构及其空间变化规律,可为海口市地下水资源的管理和利用提供依据。     

垃圾渗滤液污染地下环境物质变化对污染缓冲的影响

通过砂柱模拟实验研究垃圾渗滤液污染地下环境中氧化还原环境和主要组成物质的变化对沉积物的pH缓冲能力和氧化还原能力的影响及其相互关系.结果表明,氧化还原环境的变化对地下环境沉积物的pH缓冲和氧化还原缓冲能力有重要影响,产甲烷带/硫酸盐还原带(MGZ/SRZ)、铁还原带(IRZ)、硝酸盐还原带(NRZ)和氧还原带(ORZ)沉积物的pH缓冲容量相对于本底值分别增加了12.4%、 10.8%、 19.8%和11.1%;pH缓冲和氧化还原缓冲之间相互影响、相互促进,它们直接影响着地下环境中污染物的自然衰减作用;沉积物中的铁氧化物、有机质、SO_4~(2-)和NH_4~+-N等的含量对pH缓冲能力和氧化还原缓冲能力均有不同的影响,整个体系的污染缓冲能力是各组分的综合作用结果.