Numerical simulation of pollutant diffusion and decay process after a walter pollution incident in the Three Gorges Reservoir

We established a hydrodynamic model to simulate the pollutant transport and decay process in the case of a pollution incident in the sections of the Yangtze and the Jialing passing through the city area of Chongqing. The Boussinesq assumptions and the Navier-Stokes equations of incompressible fluid were applied to setting up the pollutant diffusion equations and the equations for the decay process. E. coli was taken as the example pollutant, and chloride dosage, light, temperature and ultraviolet intensity were considered in the equations for bacterial decay process. The calculated values of the fluid velocities in the two rivers agree well with corresponding measured results, indicating an ideal accuracy of the model. In simulation, the concentration of E. coli in water was assumed to be zero before the accident. The upriver boundary velocity was (1.35 m/s for the Jialing flow and 1.75 m/s for the Yangtze flow, and the downriver boundary was water depth set at 0. Simulation results show that the bacteria are transported downstream along the riverbank. A long and narrow pollutant belt develops at 12 h after the start of the accident ascribed to the quick longitudinal transfer. After the pollution sources are cut off, the pollutant concentration decreases slowly, mostly by advection and diffusion, suggesting inadequate self-purification ability of the rivers and the necessity of effective decontaminating measures in the case of a pollution incident. The model can be a useful tool for understanding the polluting situations of an improper discharge incident and evaluating the effects of decontaminating measures for the water body of the Three Gorges Reservoir.     

长江水质评价与预测模型

讨论了长江水质评价与预测问题,根据过去长江水质污染状况,建立的模糊优化评价模型,差值评判模型,水质污染回归模型及污水处理函数,评价且预测了长江水质污染情况,对长江水质污染问题的解决有一定的现实指导意义,提出的建议是切实可行的.     

长江水质的评价和预测

针对长江水质问题,先用内梅罗水质污染指数法对长江近两年多的水质情况做定量的综合评价,判断出主要污染物的源头所在地区,然后采用GM(1,1)模型对长江未来10年水质污染的发展趋势做出了预测．     

两种环境管理手段的厂级污染控制有效性分析

环境管理有多种手段,如适合社会经济发展,将能确保实际操作的效率。我国目前实行以污染物排放标准为基础,辅之以排污收费等多种经济形式结合的混合管理手段,在市场经济高速发展的现状表现出一定的局限性。本文以粤西某石化企业废水治理情况为例,从环境标准及排污收费标准两者与企业个体治理费用的关系出发,运用环境计量经济模型从厂级污染控制的层面上探讨了这两种环境管理手段的有效性,以期为政府制订环境政策、企业政策、宏观污染治理和进行环境管理提供参考,并可为企业环境经济效益的估算、区域工业废水控制规划和环境战略的研究等领域提供依据。     

丹江口水库面源污染调查及治理方法探究

以丹江口水库临近三个省份的5个市的调查数据为依据,建立相关的污染物排放估算模型,采用参数计算、对比分析的研究方法,对污染物中所含化学物质(如氨、氮、COD)及其入河量进行估算.结果发现:入库污染总量中,面源污染占绝对优势;在空间分布上,以南阳盆地和十堰地区贡献占绝对优势,库区区间贡献率较小;在化学元素的形态特征上,对水体的影响主要是以溶解态为主的氮和以颗粒状为主的磷.从面源污染的源头来看,不合理的土地利用造成的土壤侵蚀,薄弱的生态环境所造成的污染物转移,都是造成面源污染步步加深的原因.针对以上对汉中、南阳等5个市之间面源污染总量差异的分析,因地制宜地提出未来丹江口水库农业面源污染治理的科学对策,为丹江口库区的环境保护提供科学依据和借鉴.     

应用灰色关联分析法评价嘉陵江南充段水质

为比较清晰的了解嘉陵江水质,利用嘉陵江南充段3个监测点的近3年的实测资料(2001~2003年)。采用灰色关联分析法并引入叠加综合指数模型,对其水质进行了评价。找出了对南充河段有影响的水体主要污染物,分析形成的原因,为嘉陵江南充段水资源保护、管理提供了科学依据。     

茂名近岸海水中有机污染监测及趋势分析

2003~2005年茂名近海海域的有机污染物监测结果表明,茂名近岸海水养殖区和近海海域的有机污染物均未超过国家海洋和渔业用水标准。其中2003年和2004年变化较小,2005年下降较为明显,落潮期有机物污染比涨潮期相对严重,秋季海水中有机物污染较为严重,春季和夏季污染程度较低。有机物污染呈逐年下降的趋势,但是养殖区水质已受到近岸海水污染的影响。     

等标污染负荷法在韶关市水环境污染源评价中的应用

通过分析统计韶关市各河流的点源和面源入河污染物的等标负荷,来确定韶关市水环境的主要污染源和主要污染物,进而对韶关市各水资源市级区和县级行政区的污染源进行评价,有针对性提出一些保护韶关市水环境、预防水污染的措施与建议.     

Artificial neural network modeling of water quality of the Yangtze River system: a case study in reaches crossing the city of Chongqing

An effective approach for describing complicated water quality processes is very important for river water quality management. We built two artificial neural network （ANN） models, a feed-forward back-propagation （BP） model and a radial basis function （RBF） model, to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing, P. R. China. Our models used the historical monitoring data of biological oxygen demand, dissolved oxygen, ammonia, oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models, the RBF model calculates with a smaller mean error, but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the structures of neural network water-quality models.     

基于扩散方程的污染物传播模型

根据样点数据,利用Surfer软件,采用克里格插值法进行最优内插,绘制了城市土壤重金属分布图;采用卡梅罗综合指数评价法,考虑不同重金属元素对人体健康的影响,修订了评价指标的权重,构建了城市土壤污染评价体系;运用聚类分析模型和方差分析模型,说明重金属污染的主要原因;建立污染物浓度扩散的偏微分方程模型,通过区域划分、方程简化和最小二乘法,求出了污染源的地理位置;分析污染物扩散方程优缺点,提出了推广和拓展的设想。     

黄河三角洲水质污染对淡水底栖动物多样性的影响

1993~1997年对黄河三角洲内8条河流、3个水库和1个湖泊水质连续5年监测,1996~1997年对淡水底栖动物多样性开展了同步调查.水质评价结果:2条河流严重污染,6条河流重污染,麻大湖严重污染.淡水底栖动物共鉴定出69种,隶属于38科62属.水质污染已导致底栖动物多样性减低.     

浅析农村水域污染特征及其防治措施

本文论述了我国现阶段农村水域污染现状,分析了我国农村水域污染的特点及造成农村水污染的主要原因,并从农村水污染源头控制与利用、水污染处理过程等几方面提出农村水域污染防治措施。     

山西省黄河流域的水环境问题

山西省黄河流域是我国能源重化工基地，这里山多林少，河多水少，特殊的自然地理条件和经济结构与布局，导致水资源短缺，水环境急剧恶化，近七成河水失去使用功能，过半城市地下水被污染，水体污染主因已由工业废水变为城市生活污水；地下水过量开采，水位下降；采煤破坏了水环境，使水资源在数量上每年减少，在质量上日趋恶化； 水土流失加剧，堵塞河道，淤积水库，使脆弱的生态环境到了难以承受的边缘。     

涡河亳州境内水污染状况分析

在涡河亳州境内水质实测资料的基础上,分析区域内的亳州、涡阳、蒙城的四个水质监测断面水污染现状,并将三市县各排污口污染物总排放量采用等标污染负荷法进行评价,分析了涡河水污染特征,确定其主要污染物和主要污染源。在此分析基础上,结合分析区域的社会经济和自然环境条件,对污染原因进行探讨分析,并相应的提出有针对的防治措施和具体要求。     

主成分分析方法在长江水质评价中的应用

利用主成分分析方法对长江流域的水质进行了评价,通过MATLAB软件计算,对长江流域17个地区的污染状况作出了评价排序,并建立了稳定水质的数学模型,确定干流上的变化,找出了主要污染物高锰酸盐和氨氮的分布地区,分析结果与实际相符,具有一定可靠性和实用性.     

九龙江北溪水体营养盐来源及污染负荷分析

从工业点源、畜禽养殖、生活污水和农田径流4个方面对北溪水体污染物来源进行估算和分析。对总磷和总氮两项污染指标采用狄龙模型进行水体纳污负荷的分析。分析结果得出,九龙江北溪上游的污染主要源自畜禽养殖和生活污染。     

试论染色废水的生物处理技术

染色废水的处理的难易程度取决于染料降解的机理.在目前的染色废水处理过程中有好氧处理、厌氧处理和好氧———厌氧联合处理等生物处理方法.实践证明好氧———厌氧处理法比较实用.     

Numerical simulation of pollutant transport and accumulation areas in the Hangzhou Bay

Based on the COHERENS model (a coupled hydrodynamic ecological model for regional and shelf seas), a numerical hydrodynamic model of the Hangzhou Bay, influenced by tide, regional winds and freshwater from the Yangtze River and the Qiantangjiang River was established. The Lagrangian particle tracking was simulated to provide tracer trajectories. For convenience, the modeling area was divided into 8 subdomains and the modeling focused on March (dry season) and July (wet season). Numerical simulation and analysis indicate that the tracer trajectories originated in different subdomains are quite different. Most particles released in the mouth of the bay move outside the bay quickly and reach the farthest place at 122.5°E; while particles released in the inner part of the bay mostly remain in the same subdomain, with only minor migrations in two opposite directions along the shore. The tracer experiments also indicate that the northwest region of the bay is an area where pollutant can easily accumulate in both wet and dry seasons, and that the southeast region of the bay is another area for pollutant to accumulate in dry season because it is the main path for the contaminant.     

Mercury pollution in the Chongqing part of the Three Gorges Reservoir area and its remediation and prevention

Mercury pollution in the Three Gorges Reservoir area of P. R. China merits special attention. We investigated into the current situation in the Chongqing part of the Reservoir area, identified the pollution sources and proposed some suggestions for the remediation and prevention of mercury pollution in this area. Atmospheric mercury in Chongqing was mainly from coal burning and releases of mercury-containing products such as various types of lights and fever thermometers. Urban drainage in Chongqing and Changshou, and runoffs from the high mercury background area in the lower reaches of the Wujiang River contributed most of the mercury in the water of the Yangtze River. A majority of the blame should be laid on mercury and gold mining in the Wujiang valley. We suggested foresting sloping lands to relieve soil erosion and prevent mercury-bearing soil from running into rivers, educational activities to discourage use of mercury-containing products and improved infrastructure to collect mercury-containing wastes for reducing mercury releases, more facilities for treating wastewater and solid waste to accommodate increased requirements of discharge, and growing selected perennial plants in mercury-contaminated land to absorb the mercury in soil. We also suggested concerted operation of a dedicated water-quality monitoring system, reinforced legislation and an effective administrative mechanism to ensure lasting efforts are invested in curbing mercury releases and restoring mercury contaminated land and water in the Reservoir area.     

变化环境下保山市水资源保护对策

自2003年保山市政府批准实施《保山市水资源保护规划》以来,保山市主要江河、水库和集中供水水源地水质有所好转,但目前仍有部分河段、水库、水源地水质污染严重,加之水资源时空分布不均匀,从而导致水资源供需矛盾非常突出;通过分析自然和人类活动双重作用下水循环过程对保山市水资源的影响,结合主要水环境问题,遵循生态水文学所倡导的生态修复和可持续发展理念,提出了相应的水资源保护对策。