微细水雾除尘技术的实验研究

分析了煤矿并下呼吸性粉尘防治技术现状，并对水的超声雾化技术进行了实验研究，应用回归分析建立了超声雾化性能的数学模型。在分析微细水雾捕尘机理及捕尘水雾凝并沉降技术的基础上，设计了一集微细水雾捕尘-凝聚、凝并降尘-惯性沉降分离为一体的含尘气流净化系统，并对该系统的除尘效率进行了实验研究，建立了相应的数学模型。     

地下渗滤系统在污水处理中的应用研究进展

地下渗滤系统是一种基于自然生态原理的污水净化技术 ,在我国有着良好的可行性和发展前景。本文总结介绍了地下渗滤系统的类型 ,概括分析了地下渗滤系统中的关键性问题———土壤的选择与配制、水力负荷的选取、氮磷去除问题和土壤堵塞问题     

复合植物床式人工湿地研究

本实验研究针对应用于面源污染控制的人工湿地中水生植物的选择和布置问题进行研究,通过对人工湿地动态运行实验的研究考察,发现床体中COD、TN降解规律,通过人工湿地栽种不同水生植物的各床体的COD去除效果比较实验和不同水生植物复氧性能比较实验,得出复氧性能最好的水生植物为芦苇,然后综合这三个实验,在传统的植物床系统基础上,提出更加有利于提高系统污水处理效率的改进形式:复合植物床式人工湿地。     

潜流人工湿地污染河水处理系统中的填料堵塞问题研究

利用潜流人工湿地系统处理污染河水,水力负荷为0.15 m3/(m2·d).研究了该系统长期运行过程中的填料堵塞问题及其对污染物去除率的影响.构建了潜流人工湿地污染河水处理中试系统,在运行两年后,潜流人工湿地填料存在一定的堵塞现象,填料孔隙率最大减少了2.67%.填料孔隙堵塞现象主要发生在该中试系统的前段(沿水流方向距进水点0～5 m),其填料堵塞物质主要为无机颗粒物.植物对填料堵塞问题的改善作用并不显著.填料的部分堵塞对该中试系统中污染物的去除率有一定的影响,运行第2年氨氮的去除率略有降低,而COD的去除率有增加的趋势.     

处理生活污水的植物品种的筛选

以小型碎石床人工湿地生态系统和无土栽培2种方法,模拟研究了广东园林绿化中常用的27种植物对生活污水中氮、磷、COD的降解能力,表明野芋头、花叶万年青、象草、姜花、绿公主、富贵竹、再力花、大花叶万年青、芦苇、花芦苇、美人蕉、文殊兰、水芋头、风车草、红草、蜘蛛兰、千手观音、水葱和花蝴蝶等18种植物,可以作为人工湿地生态系统选种植物,从而扩大了可选植物品种范围,配合适当,可达到美化环境和净化污水2种功能,可适用于面源性水污染的治理.象草的研究表明,它是一种既有强污水降解能力又能作饲料的品种,适用于畜牧场的水污染治理.     

Migration of saline solutions in variably saturated porous media

Migration of concentrated NaNO3 solutions in homogeneous packs of pre-wetted silica sands was investigated using a light transmission system. Solutions of 5 molal NaNO3 were found to migrate downward 24-62% faster than pure water, in an unstable, fingered manner. This behavior was attributed primarily to a surface tension induced, non-zero apparent contact angle between the imbibing and the resident fluids. For saline solutions of similar surface tension to that of pure water (achieved by the addition of 2% methanol), the migration rates and plume shapes were comparable to that of water, demonstrating that density was not the primary source of the observed differences in migration patterns. At depths where resident saturation increased above residual, the migration process appeared to occur via film flow with slight changes in saturation (<4%), rather than in a series of abrupt jumps, as observed at shallower depths. A method for contact angle scaling was used to illustrate the effects of non-zero contact angles on capillary pressure-saturation curves.     

Human exposure to dioxins and furans: application of the substance flow analysis to health risk assessment

Substance Flow Analysis (SFA) is an important instrument that allows for the undertaking of environmental management for a specific contaminant. 'Control Analysis' is a tool that assesses the effect on a target flow of changes in flows forming part of a control basis set. The purpose of the present study was to perform a modeling of the annual PCDD/F flows in Tarragona Province and to apply the model for human health risk assessment. The validation of the model has been evaluated by comparing estimated fluxes with experimental values. Eleven subsystems, as well as a set of 88 flows of the system in Tarragona Province were considered. The total PCDD/F accumulation in Tarragona Province was between 62.6 and 159.5 g I-TEQ/y. Accumulation in sediments (27.9-74.6 g I-TEQ/y) and soils (35.0-80.8 g I-TEQ/y) are the two principal modes of deposition. Estimated flow in human adipose tissue means a mean intake of PCDD/F (via ingestion and inhalation) of 243 pg I-TEQ/person/day. The food chain pathway accounts for 99% of the total daily intake. As a result of the simulation, a 100% decrease in industrial emissions would cause a 1.7% reduction in the PCDD/F accumulation in humans. In turn, a 100% reduction of PCDD/Fs in the industrial waste waters would cause only an insignificant 0.1% decrease in the accumulation of PCDD/Fs in humans.     

Modeling the buoyant flow of heated water discharged from surface and submerged side outfalls in shallow and deep water with a cross flow

In this study, a three-dimensional model was used to numerically study the buoyant flow, along with its mixing characteristics, of heated water discharged from the surface and submerged side outfalls in shallow and deep water with a cross flow. Hydraulic experimental data were used to evaluate the applicability of the model. The simulation results agree well with the experimental results, particularly, the jet trajectories, the dimensions of the recirculating zone, and the distribution of the dimensionless excess temperature. The level of accuracy of the simulation results of the present study is nearly identical to that of the results conducted by McGuirk and Rodi (1978). If the heated water is discharged into shallow water where the momentum flux ratio and the discharge densimetric Froude number are high, the submerged discharge method is better than the surface discharge method in terms of the scale of the recirculating zone and the minimum dilution. In deep water, where the momentum flux ratio and discharge densimetric Froude number are low, however, the submerged discharge method had few advantages. In shallow water, the discharge jet is deflected by the ambient cross flow, while forcing the ambient flow to bend towards the far bank for the full depth. For a submerged discharge in shallow water, the recirculating zone is the largest in the lowest layer but becomes smaller in the upper layer. As the water depth increases, the ambient flow goes over the jet and diminishes the blocking effect, thereby decreasing the bending of the jet.     

淀山湖湿地及其生态功能与利用

淀山湖是上海市唯一的淡水湖泊，面积约６２ｋｍ２。淀山湖湿地的形成主要是地质、地貌、气候、水文等自然因素和人类活动影响长期相互作用的结果。本文着重讨论了淀山湖湿地的生产功能和环境生态功能，并对湖泊湿地的利用与保护提供了建议。     

Kelvin–Helmholtz Instability as a Boundary-Value Problem

The Kelvin–Helmholtz (KH) instability is traditionally viewed as an initial-value problem, wherein wave perturbations of a two-layer shear flow grow over time into billows and eventually generate vertical mixing. Yet, the instability can also be viewed as a boundary-value problem. In such a framework, there exists an upstream condition where a lighter fluid flows over a denser fluid, wave perturbations grow downstream to eventually overturn some distance away from the point of origin. As the reverse of the traditional problem, this flow is periodic in time and exhibits instability in space. A natural application is the mixing of a warmer river emptying into a colder lake or reservoir, or the salt-wedge estuary. This study of the KH instability from the perspective of a boundary-value problem is divided into two parts. Firstly, the instability theory is conducted with a real frequency and complex horizontal wavenumber, and the main result is that the critical wavelength at the instability threshold is longer in the boundary-value than in the initial-value situation. Secondly, mass, momentum and energy budgets are performed between the upstream, unmixed state on one side, and the downstream, mixed state on the other, to determine under which condition mixing is energetically possible. Cases with a rigid lid and free surface are treated separately. And, although the algebra is somewhat complicated, both end results are identical to the criterion for complete mixing in the initial-value problem.