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861.
文献^[1]中提出了分散体系、分散介质、分散相的概念,前文^[2]认为水体是以水为分散介质的复合三元分散体系,本文认为水体是以水为分散介质的复合四元分散体系,分散相是:①粗分散相,②假胶体^[3]分散相,③真胶体^[3]分散相,④分子离子分散相。分散体系中分散相的分离方法的理论(方法)是给水(排水)处理理论(方法)之一。 相似文献
862.
863.
William J. Elliot 《Journal of the American Water Resources Association》2004,40(2):299-309
ABSTRACT: The Water Erosion Prediction Project (WEPP) is a physically based erosion model for applications to dryland and irrigated agriculture, rangeland, and forests. U.S. Forest Service (USFS) experience showed that WEPP was not being adapted because of the difficulty in building files describing the input conditions in the existing interfaces. To address this difficulty, a suite of Internet interfaces with a database was developed to more easily predict soil erosion for a wide range of climatic and forest conditions, including roads, fires, and timber harvest. The database included a much larger climate database than was previously available for applications in remote forest and rangeland areas. Validation results showed reasonable agreement between erosion values reported in the literature and values predicted by the interfaces to the WEPP model. 相似文献
864.
H. Evan Cornfield Vicente L. Lopes 《Journal of the American Water Resources Association》2004,40(2):321-332
ABSTRACT: A process based, distributed runoff erosion model (KINEROS2) was used to examine problems of parameter identification of sediment entrainment equations for small watersheds. Two multipliers were used to reflect the distributed nature of the sediment entrainment parameters: one multiplier for a raindrop induced entrainment parameter, and one multiplier for a flow induced entrainment parameter. The study was conducted in three parts. First, parameter identification was studied for simulated error free data sets where the parameter values were known. Second, the number of data points in the simulated sedigraphs was reduced to reflect the effect of temporal sampling frequency on parameter identification. Finally, event data from a small range‐land watershed were used to examine parameter identifiability when the parameter values are unknown. Results demonstrated that whereas unique multiplier values can be obtained for simulated error free data, unique parameter values could not be obtained for some event data. Unique multiplier values for raindrop induced entrainment and flow induced entrainment were found for events with greater than a two‐year return period (~25 mm) that also had at least 10 mm of rain in ten minutes. It was also found that the three‐minute sampling frequency used for the sediment sampler might be inadequate to identify parameters in some cases. 相似文献
865.
微生物絮凝剂及其在污水处理中的应用 总被引:10,自引:0,他引:10
综述了微生物絮凝的种类,性质,产生条件。讨论了影响微生物絮凝剂絮凝活性的主要因素和絮凝机理的多样性;列举了徽生物絮凝剂在水处理中的应用;最后,展望了微生物絮凝剂的研究发展方向。 相似文献
866.
867.
含络合剂(EDTA,NTA等)金属离子和COD废水是一种难治理的废水,采用通常的凝聚氢氧化物沉淀法处理是无效的,本文对络合剂铜镍离子和COD废水,首先采用加入Fe^2 140~150mg/L,控制pH4—4.5进行还原反应,然后升高pH为8.5进行网捕凝聚沉淀法处理,获得了良好效果,排放水质中的Cu、Ni均达到《上海市综合污水排放标准》,COD去除率为50%左右,因此还原-网捕凝聚沉淀法是处理含络合剂金属离子的废水值得进一步完善和应用的新工艺。 相似文献
868.
Elizabeth S. Schnackenberg Lee H. MacDonald 《Journal of the American Water Resources Association》1998,34(5):1163-1177
ABSTRACT: This study evaluated the use of a modified pebble count procedure (Bevenger and King, 1995) to detect cumulative watershed effects on headwater streams in the Routt National Forest in northcentral Colorado. The 42 sample reaches were stratified by disturbance (reference or disturbed) and geologic terrene (granitic or mixed sedimentary-volcanic). Water surface slope was a significant control on the number of fine particles in the reference reaches in both terranes, and the data from the disturbed reaches were adjusted accordingly. The disturbed reaches in the granitic terrene generally had a higher percentage of fine particles, and the adjusted number of fine particles was significantly correlated with the number of road crossings. Disturbed reaches in the sedimentary-volcanic (s-v) terrane generally did not have significantly more fine particles, nor were the adjusted numbers of fine particles significantly correlated with any management index. The lack of significant trends in the s-v streams is probably due to differences in weathering between the two rock types, and the location of the sample reach relative to sedimentary outcrops. Two other procedures were also used to assess cumulative watershed effects, with the Pfankuch channel stability rating yielding stronger and more consistent differences between the reference and the disturbed streams than the Tarzwell substrate ratio. We conclude that it may be difficult to define a standard reference condition, and that the number of road crossings is more strongly correlated with the number of fine particles than equivalent clearcut area. 相似文献
869.
Chih‐Heng Tsai Chang‐Tai Tsai 《Journal of the American Water Resources Association》2000,36(5):1075-1086
ABSTRACT: A mathematical model to predict both velocity and concentration distributions for sediment‐laden open channel flow is developed. Velocity profiles are derived by theoretical analysis and numerical method. Logarithmic law and semi‐empirical wake function concept are not adopted. An empirical equation for the ratio of sediment exchange and fluid diffusion coefficients is considered to solve the diffusion equation for suspended‐sediment concentration profiles. Four sets of experimental data from previous researchers are compared to numerical calculation. In the engineering applications, velocity and concentration profiles of sediment‐laden flow can be predicted simultaneously by the present model with the measured velocity and sediment‐concentration at reference level. 相似文献
870.
应用氧化絮凝复合床降解废水中的阴离子表面活性剂,系统地研究了各种主要的物理化学因素;催化剂种类、填料颗粒粒度、槽电压、电极间距离、压缩空气流量、试样的浓度、酸度、电导率和处理时间等对阴离子表面活性剂去除效果的影响,找到了相关的影响规律,确定了最佳的物理化学条件,实验结果表明,阴离子表面活性剂的去除率在95%以上,出水的水质可以达到国家的排放标准。 相似文献