A two-dimensional water-quality model for a winding and topographically complicated river

In this paper, a two-dimensional numerical calculation algorithm for water-quality modeling is presented. The algorithm is designed specifically for river systems with complicated geometric conditions. When velocity field data of the river are not available, the numerical calculation algorithm for the water-quality modeling can be used to project river-water quality by using a topographic map of the river course and a finite element method. The calculation results of the water-quality model can show the concentration fields of various pollutants. The water-quality model was applied to a case-study in the Hengyang City section of Xiangjiang River in Hunan Province, China. The river under consideration is winding and has an isle between two branches. In 1995, Chinese government secured a World Bank loan to conduct a Waterways Project in the study region. It was expected that construction works in the river section might affect water quality. Given that the project would change the hydrological regime of the river system and discharges, and so would affect water quality, there would be a need for model results that would predict the water-quality impacts of the Waterways Project. In particular, the study intended to apply the model to identify changes in river-water quality associated with the construction of Dayuandu navigation key project. It is hoped that the numerical calculation algorithm for the water-quality modeling presented in this paper can also be applied to other shallow rivers with similar topographical conditions.     

Oxidative pretreatment accelerates TNT metabolism in soils

The combined effect of ultraviolet (UV)-ozonation (O₃) of aqueous ¹⁴C-TNT solutions followed by direct addition of the solutions to aerobic soils was examined as a method of disposal. The effect of TNT concentration was studied on both UV-O₃ and soil metabolism. The amount of TNT degraded by either process decreased as the concentration increased. UV-O₃ of a 1 ppm solution of TNT using a laboratory 450 W lamp for 10, 20, and 30 minutes resulted in substantial fragmentation of the ring and an increase in polarity of the resultant products. Soil metabolism, as measured by metabolic CO₂ evolution, increased as the time of prior UV-O₃ increased. A large amount of the ¹⁴C associated with ¹⁴C-TNT recovered from soil was in the non-extractable fraction. When a , adapted to metabolize -nitrophenol or picric acid as a sole source of carbon and nitrogen, was substituted for the soil phase, about 25% of the added ¹⁴C appeared as ¹⁴CO₂. 1,3,5-Trinitrobenzene, 2,4,6-trinitrobenzaldehyde, 3,5-dinitrophenol, 3, 5-dinitrocatechol, 3,5-dinitrohydroquinone, and oxalic acid were identified as products of UV-O₃. Rapid destruction of TNT took place in a large 66 lamp unit, and the resultant distribution of ¹⁴C was similar to the results from the laboratory studies.     

Evaluation of modified clay coagulant for sewage treatment

The use of modified clays as coagulants for sewage treatment was investigated in this study. The raw clays were montmorillonites K10 and KSF, and were modified by polymeric Al or Fe and/or Al/Fe mixing polymeric species. The comparative performance of modified clays and aluminium sulphate and ferric sulphate were evaluated in terms of the removal of turbidity, suspended solids, UV(254)-abs, colour, and total and soluble CODs. The results demonstrated that after being modified with mixing polymeric Al/Fe species, two montmorillonite clays possess greater properties to remove the particles (as suspended solids) and organic pollutants (as COD and UV(254)-abs) from the sewage and to enhance the particle settling rate significantly.     

Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L)

Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L) were studied in a pot experiment by measurement of fresh weights of the plants, determination of surperoxide dismutase (SOD), peroxidase (POD), and lipid peroxidation (MDA) in the plant organs, and observation of injury symptoms. The experimental results demonstrated that all treatments of Cd2+, Zn2+, and/or acid rain significantly decreased fresh weights of kidney bean and caused toxic effects on growth of the plants, especially higher amounts of Cd2+ and Zn2+ and higher acidity of acid rain. Combination of these three pollutant factors resulted in more serious toxic effects than any single pollutant and than combinations of any two pollutants. SOD, POD, and MDA in the plant organs changed with different pollution levels, but MDA content in the leaves showed the best relationship between the pollution levels and toxic effects.     

驱排剂解堵工艺的研究与应用

吐哈温米油田属于低孔、低渗、低产能油藏,原油含蜡量、沥青质较高,油井的近井地带结垢严重。文章介绍了驱排剂的解堵作用原理、酸化工作液配方、驱排剂解堵工艺技术和现场应用效果。研究结果表明,驱排剂解堵工艺技术对解除油井的堵塞具有良好的效果,对提高油井的产液能力有重要作用,同时又是低渗透油田增产的一种新工艺。从2004年7月份开始,温米油田利用驱排剂解堵后油井平均单井日增油量3.0t,日增液量21.0t,动液面平均上升400.00m,平均单井有效生产期为90天以上。     

利用人工降雨手段化汛期特大暴雨灾害为可利用水资源

利用美国1979-1995年NCEP/NCAR再分析及其它格点资料进行分析。发现汛期影响我国特大暴雨及洪涝灾害的，是一支存在于南，北两半球之间的非亚支“宏观气流系统”，它的气流运行具有一定的规律性，因而，对我国的特大暴雨和洪涝灾害，不但可以进行及时的监测和预报，而且可以在这支宏观气流系统的上游地带施行人工影响云雨工程，把空中丰沛水分降到需要雨水的地区，化洪涝灾害为宝贵的水资源。     

Application of numerical simulation on optimum design of two-dimensional sedimentation tanks in the wastewater treatment plant

The paper establishes the relationship between the sttling efficiency and the sizes of the sedimentation through the process of numerical simulation,which is taken as of the constraints to set up a simple optimum dsigning model of sedimentation tank.The feasibility and advantages of this model based on numerical calculation are verified through the application of practical case.     

论新形势下如何做好建设项目环境管理工作

本文根据作者多年从事建设项目环境管理工作的经验体会,分析了当前建设项目环境管理工作面临的形势,论述了做好建设项目环境管理工作应着重把握的几个问题     

微生物酸化的生产应用研究

分析了折流式酸化池在抗生素废水处理工程中的运行效果和水质变化对酸化作用的影响。实践证明经微生物酸化 ,CODCr去除率达到 1 4%～ 1 9% ,出水VFA增量达 2 .0倍以上。     

灰色动态模型在环境系统分析和预测中的应用

以焦作市人类-环境系统为实例,探讨了灰色动态模型在环境系统分析、预测中的应用。