分层锰砂滤池去除地下水中铁离子的工程应用

通过工程实例讨论了分层锰砂滤池在地下水去除铁离子中的工艺过程和处理效果。结果表明:滤池对铁离子有较好的去除效果,进水中铁离子浓度由1.57 mg/L降到出水的0.06mg/L,去除率达到96%以上。与传统的锰砂滤池相比,由于采用了适当的预处理以及滤料的分层设计,系统的堵塞情况大为改善,反冲洗频率大幅降低,运行管理更加方便。     

Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds1

Watson, Tara K., Dorothy Q. Kellogg, Kelly Addy, Arthur J. Gold, Mark H. Stolt, Sean W. Donohue, and Peter M. Groffman, 2010. Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 46(2):237-245. DOI: 10.1111/j.1752-1688.2010.00418.x Abstract: We evaluated the relationship of dominant watershed land use to the structure and nitrogen (N) sink function of riparian zones. We focused on groundwater denitrification capacity, water table dynamics, and the presence and pattern of organically enriched deposits. We used the push-pull method (measurement of ¹⁵N-enriched denitrification gases derived from an introduced groundwater plume of ¹⁵N-enriched nitrate) to evaluate groundwater denitrification capacity on nine forested wetland riparian sites developed in alluvial or outwash parent materials in southern New England. Three replicate sites were located in each of the three watershed types, those with substantial (1) irrigated agriculture, (2) suburban development, and (3) forest. Soil morphology and water table dynamics were assessed at each site. We found significantly lower mean annual water tables at sites within watersheds with substantial irrigated agriculture or suburban development than forested watersheds. Water table dynamics were more variable at sites within suburban watersheds, especially during the summer. Groundwater denitrification capacity was significantly greater at sites within forested watersheds than in watersheds with substantial irrigated agriculture. Because of the high degree of variability observed in riparian sites within suburban watersheds, groundwater denitrification capacity was not significantly different from either forested or agricultural watersheds. The highly variable patterns of organically enriched deposits and water tables at sites within suburban watersheds suggests that depositional events are irregular, limiting the predictability of groundwater N dynamics in these riparian zones. The variability of riparian N removal in watersheds with extensive suburbia or irrigated agriculture argues for N management strategies emphasizing effective N source controls in these settings.     

Sensitivity of Stream flow and Water Table Depth to Potential Climatic Variability in a Coastal Forested Watershed1

Dai, Zhaohua, Carl C. Trettin, Changsheng Li, Devendra M. Amatya, Ge Sun, and Harbin Li, 2010. Sensitivity of Streamflow and Water Table Depth to Potential Climatic Variability in a Coastal Forested Watershed. Journal of the American Water Resources Association (JAWRA) 1–13. DOI: 10.1111/j.1752-1688.2010.00474.x Abstract: A physically based distributed hydrological model, MIKE SHE, was used to evaluate the effects of altered temperature and precipitation regimes on the streamflow and water table in a forested watershed on the southeastern Atlantic coastal plain. The model calibration and validation against both streamflow and water table depth showed that the MIKE SHE was applicable for predicting the streamflow and water table dynamics for this watershed with an acceptable model efficiency (E > 0.5 for daily streamflow and >0.75 for monthly streamflow). The simulation results from changing temperature and precipitation scenarios indicate that climate change influences both streamflow and water table in the forested watershed. Compared to current climate conditions, the annual average streamflow increased or decreased by 2.4% with one percentage increase or decrease in precipitation; a quadratic polynomial relationship between changes in water table depth (cm) and precipitation (%) was found. The annual average water table depth and annual average streamflow linearly decreased with an increase in temperature within the range of temperature change scenarios (0-6°C). The simulation results from the potential climate change scenarios indicate that future climate change will substantially impact the hydrological regime of upland and wetland forests on the coastal plain with corresponding implications to altered ecosystem functions that are dependent on water.     

西北煤炭开发生态风险管控区划分及管理策略

为维护我国西北地区生态安全,引导煤炭资源有序开发利用,以甘肃省、青海省、新疆维吾尔自治区为研究区域,结合西北地区典型内陆河流域地下水形成特征及区域生态环境特点,选取与区域煤炭综合开发活动具有重要关联的地下水资源、生态环境等指标,利用专家打分法确定评价指标权重,构建煤炭综合开发生态风险管控评价指标体系,通过对指标体系分级结果的空间转化,划分禁止开发区、限制开发区、适度开发区3个煤炭开发的生态风险管控区.结果表明:①禁止开发区面积约131.6×104 km2,占西北三省（自治区）总面积的46%,主要分布在柴达木、塔里木、准噶尔三大盆地的盆周及周边地区,总体上呈"三环"分布,禁止开发区应禁止一切煤炭开发活动.②限制开发区1区主要分布在新疆维吾尔自治区南部地区及天山北麓以及甘肃省河西走廊的人工绿洲,煤炭开发利用过程中要兼顾保护农田、地下水,维持防风固沙功能方可进行;限制开发区2区主要分布在甘肃省酒泉地区黑河流域,新疆维吾尔自治区阿克苏地区、喀什地区及和田地区的荒漠生态系统内以及环塔里木盆地外围地区,煤炭开发利用过程中需兼顾防风固沙功能及生态系统保护方可进行.③适度开发区分布较为分散,在保护特定生态系统功能的前提下可适度开发.研究显示,需针对上述不同类型的生态风险管控区提出差别化管理要求,重点对限制开发区、适度开发区的煤炭开发提出相应的生态保护要求,提出由限制为主转向优化发展为主的管理方略.      

某石油污染地下水溶解性无机碳低异常的微生物地球化学成因探析

微生物地球化学作用往往导致石油污染场地地下水中溶解性无机碳(DIC)升高,而华北某石油污染场地地下水DIC低异常明显.为究其机理,在水文地球化学分析和16S rRNA基因高通量测序基础上,结合含水层结构及流场特征,剖析了地下水水化学和微生物两方面作用,辨识了地下水中DIC变异的主导因素,揭示了其中的生物地球化学作用的机理,发现该场地地下水DIC低异常可能与地下水中具有较高浓度钙镁离子和较高活性自养微生物有关,自养微生物代谢及诱导产生碳酸盐岩沉淀作用极可能是该场地地下水中DIC低异常的成因.推测机理为:Hydrogenophaga和Sedimentibacter等菌属微生物在氢化酶的作用下产氢气,Hydrogenophaga、Pseudomonas、Pseudoxanthomonas、Polynucleobacter等固碳微生物和产甲烷微生物利用氢气作为能源,将DIC合成有机碳,并产生碱性微环境,促使Ca~(2+)和Mg~(2+)与DIC反应形成碳酸钙镁沉淀.     

黄河下游影响带地下水资源评价及合理开发利用

论文研究黄河下游影响带(河南段)地下水资源评价及合理开发利用问题。在概要介绍河南省黄河影响带水文地质条件基础上,运用FEFLOW建立研究区三维地下水流模型,计算出地下水多年平均补给资源28.35×10⁸m³/a和可开采资源量19.43×10⁸m³/a。重点阐述新增9个水源地的开采条件,并通过地下水模型预测新增133×10⁴m³/d开采量条件下,浅层地下水位最大降深小于20m,开采5～10年后地下水趋于稳定,新增开采量的62.58%来自黄河水的补给。研究表明,黄河对研究区地下水具有重要的补给作用,新增地下水开采量是有保证的。同时阐述了研究区地下水可持续开发利用的对策。     

应用ORP预测和控制地下水除铁滤池出水含铁量

试验研究了应用氧化还原电位(ORP)预测和控制除铁滤池出水含铁量的可行性,探讨了水力负荷(HLR)、溶解氧(DO)和pH值对ORP和滤池除铁效果的影响以及曝气过滤除铁的机理.结果表明,在pH值为6.69,DO为6.8mg/L时,滤池除铁机理主要为接触催化氧化作用;HLR、DO和pH值对滤池除铁有较大的影响;滤池出水含铁量(Y)与ORP(X)之间的关系可用回归方程Y=0.0004exp[3816/(X+200)] (R2=0.9664)表示;当ORP在400~510mV时,滤池出水含铁量小于0.3mg/L.     

改进突变模型在地下水开发风险评价中的应用研究

地下水资源的不合理开采对生态环境和人类健康势必造成严重危害,对地下水开发利用进行有效的风险识别与评价,可为水资源综合规划和科学管理奠定基础和提供参考依据。本文以下辽河平原7个行政区域为研究区,构建适宜该区地下水开发风险评价的指标体系,基于改进的突变模型,计算研究区内各行政区的地下水开发风险综合值。结果表明,下辽河平原地下水开发风险较严重,在今后的开发利用过程中需采取有效措施,以实现地下水资源的可持续开发与利用。     

尾矿库渗滤液对地下水环境影响评价研究——以一电解金属锰项目尾矿库为例

金属锰冶炼产生的压滤渣在堆存过程中由于降雨及渣体自带水分产生含高浓度Mn、Cr6+的渗滤液,一旦泄漏,将污染下游地下水。结合具体实例,按照《环境影响评价技术导则地下水环境》要求,对一尾矿库渗滤液泄漏对下游地下水环境特别是生活水源的影响进行评价,评价结果显示,若发生渗滤液泄漏,将导致下游地下水Mn、Cr6+超标,但不会对生活水井产生直接影响,在此基础上,针对泄漏风险,对尾矿库现有防渗措施进行评价,并进一步提出相应的防范措施。     

地下人防项目地下水环境影响评价技术评估要点研究

地下人防项目是指战时用于人员、物资掩蔽,平时为商业用途的地下工程。地下人防项目地下水环境影响评价技术评估,应遵循《环境影响评价技术导则地下水环境》(HJ 610-2011)相关要求,结合项目场区所在地的地下水水位、地下水分布及环境水文地质条件、污染源状况、地下水开采利用状况及具体施工情况,分析地下水水位变化诱发的环境水文地质问题的影响范围、程度及项目建设对地下水水质污染,重点关注水位变化分析和地面沉降分析,污染防治措施主要从防治地下水水质污染、环境水文地质问题两方面考虑。