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241.
当前,我国突发环境事件中涉水事件占比较高,生态环境风险较大。通过分析近年来国内突发水污染事件典型案例的特点及国家环境应急管理政策,结合多次参与事件应急处置及调查等环境应急支撑工作中的一些思考,从应急控制标准制定、应急平台建设、应急技术研究、智慧应急4个方面,分析我国突发水污染事件应急处置技术的发展需求及未来研究方向,旨在为建立健全突发水污染事件应急处置技术体系、提高国家环境应急能力提供参考。
相似文献242.
为了快速净化景观湖泊的补水,采用磁絮凝法对Ⅴ类甚至劣Ⅴ类河道水体进行预处理,设计正交试验,分析了絮凝剂(PAC)、助凝剂(PAM)以及磁铁粉的投加量对预处理效果的影响,并利用正交试验法和多指标综合评分法进一步优化磁絮凝预处理工艺参数,结果表明最佳工艺参数为:磁铁粉加入量100 mg/L,PAC投加量150 mg/L,PAM投加量2 mg/L。在此最佳工艺参数下,进行验证试验,COD去除率达到50.39%,TP去除率为96.65%,浊度去除率为91.59%,氨氮去除率为6.31%,除氨氮外,其他各指标基本均能达到地表水环境Ⅲ类水体标准,达到了预处理目的,为后续深度净化减轻负荷压力。 相似文献
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针对仪化热电厂将循环水用作冲灰水,导致浓缩倍率只有1.6,以及凝汽器铜管腐蚀结垢严重等问题,提出了隔断循环水与冲灰水的直接联系,实现闲路循环,对凝汽器铜管进行酸洗,并对循环水实施加缓蚀阻垢荆、杀菌剂和旁流过滤等办法,全部实施后产生了很好的效益,值得借鉴。 相似文献
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Mark C. Stone Rollin H. Hotchkiss Carter M. Hubbard Thomas A. Fontaine Linda O. Mearns Jeff G. Arnold 《Journal of the American Water Resources Association》2001,37(5):1119-1129
ABSTRACT: Water from the Missouri River Basin is used for multiple purposes. The climatic change of doubling the atmospheric carbon dioxide may produce dramatic water yield changes across the basin. Estimated changes in basin water yield from doubled CO2 climate were simulated using a Regional Climate Model (RegCM) and a physically based rainfall‐runoff model. RegCM output from a five‐year, equilibrium climate simulation at twice present CO2 levels was compared to a similar present‐day climate run to extract monthly changes in meteorologic variables needed by the hydrologic model. These changes, simulated on a 50‐km grid, were matched at a commensurate scale to the 310 subbasin in the rainfall‐runoff model climate change impact analysis. The Soil and Water Assessment Tool (SWAT) rainfall‐runoff model was used in this study. The climate changes were applied to the 1965 to 1989 historic period. Overall water yield at the mouth of the Basin decreased by 10 to 20 percent during spring and summer months, but increased during fall and winter. Yields generally decreased in the southern portions of the basin but increased in the northern reaches. Northern subbasin yields increased up to 80 percent: equivalent to 1.3 cm of runoff on an annual basis. 相似文献
248.
Keith E. Schilling Donna S. Lutz 《Journal of the American Water Resources Association》2004,40(4):889-900
ABSTRACT: Excessive nitrate‐nitrogen (nitrate) export from the Raccoon River in west central Iowa is an environmental concern to downstream receptors. The 1972 to 2000 record of daily streamflow and the results from 981 nitrate measurements were examined to describe the relation of nitrate to streamflow in the Raccoon River. No long term trends in streamflow and nitrate concentrations were noted in the 28‐year record. Strong seasonal patterns were evident in nitrate concentrations, with higher concentrations occurring in spring and fall. Nitrate concentrations were linearly related to streamflow at daily, monthly, seasonal, and annual time scales. At all time scales evaluated, the relation was improved when baseflow was used as the discharge variable instead of total streamflow. Nitrate concentrations were found to be highly stratified according to flow, but there was little relation of nitrate to streamflow within each flow range. Simple linear regression models developed to predict monthly mean nitrate concentrations explained as much as 76 percent of the variability in the monthly nitrate concentration data for 2001. Extrapolation of current nitrate baseflow relations to historical conditions in the Raccoon River revealed that increasing baseflow over the 20th century could account for a measurable increase in nitrate concentrations. 相似文献
249.
Garey A. Fox George J. Sabbagh Robert W. Malone Ken Rojas 《Journal of the American Water Resources Association》2007,43(6):1359-1372
Abstract: Few studies exist that evaluate or apply pesticide transport models based on measured parent and metabolite concentrations in fields with subsurface drainage. Furthermore, recent research suggests pesticide transport through exceedingly efficient direct connections, which occur when macropores are hydrologically connected to subsurface drains, but this connectivity has been simulated at only one field site in Allen County, Indiana. This research evaluates the Root Zone Water Quality Model (RZWQM) in simulating the transport of a parent compound and its metabolite at two subsurface drained field sites. Previous research used one of the field sites to test the original modification of the RZWQM to simulate directly connected macropores for bromide and the parent compound, but not for the metabolite. This research will evaluate RZWQM for parent/metabolite transformation and transport at this first field site, along with evaluating the model at an additional field site to evaluate whether the parameters for direct connectivity are transferable and whether model performance is consistent for the two field sites with unique soil, hydrologic, and environmental conditions. Isoxaflutole, the active ingredient in BALANCE® herbicide, was applied to both fields. Isoxaflutole rapidly degrades into a metabolite (RPA 202248). This research used calibrated RZWQM models for each field based on observed subsurface drain flow and/or edge of field conservative tracer concentrations in subsurface flow. The calibrated models for both field sites required a portion (approximately 2% but this fraction may require calibration) of the available water and chemical in macropore flow to be routed directly into the subsurface drains to simulate peak concentrations in edge of field subsurface drain flow shortly after chemical applications. Confirming the results from the first field site, the existing modification for directly connected macropores continually failed to predict pesticide concentrations on the recession limbs of drainage hydrographs, suggesting that the current strategy only partially accounts for direct connectivity. Thirty‐year distributions of annual mass (drainage) loss of parent and metabolite in terms of percent of isoxaflutole applied suggested annual simulated percent losses of parent and metabolite (3.04 and 1.31%) no greater in drainage than losses in runoff on nondrained fields as reported in the literature. 相似文献
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