干湿交替条件下包气带土柱中氮素迁移转化规律实验

干湿交替的回灌方法常被用于解决地面回灌补给地下水的堵塞问题。研究干湿交替条件下地面回灌对地下水的影响对于指导再生水回灌地下水具有重要实际意义。通过室内土柱模拟实验,在入渗强度为10.5 mm/h的条件下,日均进水量3 888 mL;用干湿交替的地面回灌模式持续运行136 d,累计灌入氨氮含量为5 mg/L的模拟再生水23 894 L,研究包气带土柱对氨氮的去除效果及氮素在包气带中的迁移转化规律。研究表明,充分利用包气带的好氧、兼氧和厌氧环境,生物脱氮是地下水回灌过程中脱氮的主要途径。包气带对氨氮的去除机理主要为土壤对氨氮的吸附作用和微生物的降解作用。回灌过程中累积在土颗粒表面的氨氮在干期发生硝化作用,干湿交替会加强氮素在包气带的迁移转化,导致干期后的回灌初期大量硝态氮迁移到饱和带地下水中。     

再生水干湿交替回灌过程氮素动态变化特征研究

再生水地下回灌过程中,研究了前处理和含水层中氮污染物在干湿交替回灌过程中的变化特征。结果表明:回灌期间,在臭氧氧化作用下会发生硝化反应,使NH4-N平均浓度降低0.196 mg/L,NO_3-N平均浓度上升为2.26 mg/L。再生水进入含水层后,水中游离氧仍然较高(6.89 mg/L),注入井附近会继续发生硝化反应,使5#井中NH4-N下降至0.07 mg/L;NO_3-N浓度在3#井到5#井之间符合线性方程y=-0.172 8 x+31.245;NO_2-N在3#井、4#井和5#井中平均浓度分别为2.02 mg/L、2.023 mg/L和2.427 mg/L。非回灌期地下水中反硝化反应使NO_3-N降低了12.241 mg/L,NO_2-N均上升了0.918 mg/L。另外,TN的变化规律与NO_3-N类似,非回灌期5#井中TN的去除率达56.6%。     

土壤含水层处理系统对再生水入渗过程中“三氮”去除的柱试验模拟

土壤含水层处理系统(soil aquifer treatment,SAT)是一种重要的人工回灌地下水方式。以再生水为回灌水源时,水中含有的"三氮"可能会对回灌区地下水造成污染风险。研究各种因素对在SAT中去除再生水中"三氮"的影响具有重要意义。本研究中,通过高200cm、内径50cm土柱试验,研究了SAT系统中粒径、干湿比(落干期与淹水期的比值)、在系统表层增加生物炭及渗透流速对实际再生水"三氮"去除效果的影响。结果表明,在干湿比1∶1条件下,实际河道细砂和中细砂柱底部出水中NH_4-N平均去除率分别为73%和66%,去除机理主要为吸附和硝化作用,NO_2-N基本被去除。系统中硝化作用导致NO_3-N浓度升高,出水中NO_3-N浓度平均增长了3.0%～4.1%。在深度115cm以上,中细砂柱内比细砂柱内的硝化作用更强,这导致了更高的NH_4-N去除率和更低的NO_3-N去除率。延长落干期后(干湿比3∶1),系统具有了更强的复氧能力,促进了硝化作用,使得NH_4-N的平均去除率提高了20%,而NO_3-N的降低了3%～4%,增加了NO_3-N污染风险。在中细砂层添加5%重量生物炭后,吸附性能增强,使其对NH_4-N平均去除率增加了20%～32%,但对NO_3-N影响不明显。渗透流速与NH_4-N的去除和NO_3-N的增加均呈负相关。综合分析可得出,影响SAT系统去除"三氮"的最主要因素是干湿比和渗透流速,在回补水源中NH_4-N浓度较高时,可考虑在SAT系统表层添加生物炭以增强其去除效果。     

土壤含水层处理系统对再生水入渗过程中"三氮"去除的柱试验模拟

土壤含水层处理系统(soil aquifer treatment,SAT)是一种重要的人工回灌地下水方式。以再生水为回灌水源时,水中含有的“三氮”可能会对回灌区地下水造成污染风险。研究各种因素对在SAT中去除再生水中“三氮”的影响具有重要意义。本研究中,通过高200 cm、内径50 cm土柱试验,研究了SAT系统中粒径、干湿比(落干期与淹水期的比值)、在系统表层增加生物炭及渗透流速对实际再生水“三氮”去除效果的影响。结果表明,在干湿比1∶1条件下,实际河道细砂和中细砂柱底部出水中NH₄-N平均去除率分别为73%和66%,去除机理主要为吸附和硝化作用,NO₂-N基本被去除。系统中硝化作用导致NO₃-N浓度升高,出水中NO₃-N浓度平均增长了3.0%4.1%。在深度115 cm以上, 中细砂柱内比细砂柱内的硝化作用更强,这导致了更高的NH₄-N去除率和更低的NO₃-N去除率。延长落干期后(干湿比3∶1),系统具有了更强的复氧能力,促进了硝化作用,使得NH₄-N的平均去除率提高了20%,而NO₃-N的降低了3%4%,增加了NO₃-N污染风险。在中细砂层添加5%重量生物炭后,吸附性能增强,使其对NH₄-N平均去除率增加了20%32%,但对NO₃-N影响不明显。渗透流速与NH₄-N的去除和NO₃-N的增加均呈负相关。综合分析可得出,影响SAT系统去除“三氮”的最主要因素是干湿比和渗透流速,在回补水源中NH₄-N浓度较高时,可考虑在SAT系统表层添加生物炭以增强其去除效果。     

再生水地表回灌补给地下水的水质安全保障体系

把城市污水净化处理为符合回灌标准的再生水并安全回灌补给地下水, 对于实现污水资源化、含水层恢复、缓解我国水资源供需矛盾和环境污染态势具有重要意义.针对再生水回灌地下水存在的水质安全问题, 通过理论分析、系列实验和技术集成形成了再生水地表回灌补给地下水的水质安全保障体系及关键技术.该安全保障体系包括场地选择与勘查、高效低成本的再生水处理技术、土壤—含水层系统数学模型和回灌方案设计技术、水质监控系统、安全评价技术以及回灌管理法规等.这些要素相互依赖、相互作用, 构成一个完整的体系.郑州郊区示范工程证实了该水质安全保障体系的可行性.2年示范工程表明, 处理的再生水水质达到《城市污水再生利用地下水回灌水质》(GB/T 19772-2005)标准, 优于场地背景地下水水质, 补给含水层后的地下水基本达到《地下水质量标准》(GB/T 14818-1993)Ⅲ类水标准.建议有关政府部门把再生水利用及回灌补给地下水, 纳入水资源开发利用及环境保护规划的整体框架中, 尽快制定或完善再生水回灌补给地下水的相关法律、法规和标准体系, 建立再生水回灌许可证制度, 有序推进再生水回灌工程.      

基于数值模拟的再生水对地下水质影响实例

为了探讨在再生水地表回灌条件下,再生水对地下水中氨素和主要盐分浓度变化的影响,选取现实存在的清河再生水湿地公园为例,以氨氮、Cl-离子为主要研究对象,利用Hydrus-1D溶质运移模型和Modflow、MT3DMSD耦合地下水模型,模拟了再生水长期利用后的地下水氨氮和Cl-指标变化情况。研究结果显示,再生水到达包气带底部时,水中氮氨、Cl-离子含量高于研究区潜水地下水中的相应指标含量,氨氮超出地下水质量Ⅲ类标准。预测5~20年后,潜水中氨氮超标面积不断扩展,20年后将达14km2,氨氮超标垂向延伸至第一层弱透水层;Cl-离子在潜水中不超标,但在湿地公园周边浓度有所增加。湿地公园再生水的长期地表回灌将给当地地下水质量带来负面影响。     

潮白河流域人工复合地层系统去除甲氧苄胺嘧啶的模拟研究

基于潮白河流域再生水的场地回灌,为提高抗生素甲氧苄氨嘧啶（TMP）的去除率,降低其进入地下水的风险,选用价格低廉对TMP有高效去除性能的黏土陶粒作为吸附剂,构建去除TMP的人工复合土柱。吸附实验研究结果显示黏土陶粒对TMP吸附容量达到151.824 μg/g,具有去除再生水中TMP能力;TMP在黏土陶粒解吸过程中存在解吸滞后性的现象。柱实验研究结果表明此人工复合土柱能够有效地去除再生水中TMP,去除率高于95%,其去除机制主要是吸附与生物降解协同作用。本研究建立的人工复合土层系统能有效地去除再生水中TMP,对实际场地回灌工程具有指导性作用。     

北京地区地下水人工回灌简介

北京地区开展人工回灌有了近50年的历史,经历了试验和工程实施阶段。试验阶段包括深井、砂石坑、大口井回灌等试验,工程实施包括城市雨洪利用和再生水回灌利用等。     

潮白河流域人工复合土层系统去除甲氧苄氨嘧啶的模拟研究

基于潮白河流域再生水的场地回灌,为提高抗生素甲氧苄氨嘧啶(TMP)的去除率,降低其进入地下水的风险,选用价格低廉对TMP有高效去除性能的黏土陶粒作为吸附剂,构建去除TMP的人工复合土柱。吸附实验研究结果显示黏土陶粒对TMP吸附容量达到151.824μg/g,具有去除再生水中TMP能力;TMP在黏土陶粒解吸过程中存在解吸滞后性的现象。柱实验研究结果表明此人工复合土柱能够有效地去除再生水中TMP,去除率高于95%,其去除机制主要是吸附与生物降解协同作用。本研究建立的人工复合土层系统能有效地去除再生水中TMP,对实际场地回灌工程具有指导性作用。     

水库消落带岩石崩解过程中所处湿干交替作用环境模拟研究

水库运行期水库岸坡防洪限制水位及正常蓄水位之间消落带内的岩石,由于库水位的周期性变化而处在湿干交替作用的环境中.针对目前在研究水库运行期岸坡消落带软岩崩解机理过程中消落带湿干交替作用环境模拟不合理的问题,选取三峡库区三叠系巴东组中风化紫红色泥岩为研究对象,将泥岩置于室内周期性湿干交替作用的环境中,对湿化和干燥过程中泥岩崩解物的宏观质量、物质组成及微细观结构和湿化溶液的化学成分的变化进行测试.测试结果表明：崩解物的质量在湿干交替作用5个周期后不再增加;随着湿干交替作用次数的增加,黏土矿物中含量较大的蒙皂石矿物的含量在减少,第1次湿干交替作用后减少最为明显,4次后趋于稳定;随着湿干交替作用次数的增加,阳离子交换量在5个周期后变化很小.根据测试结果,确定了水库运行期消落带三叠系巴东组中风化紫红色泥岩在湿干交替作用过程中的湿化和干燥的模拟时间,即一个湿干交替作用周期的湿化时间为4天、干燥为2天;泥岩在湿干交替作用5个周期后不再崩解.研究成果为揭示水库岸坡消落带软岩崩解机理提供了消落带湿干交替作用环境的合理模拟方式.     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861